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Hurychová J, Dostál J, Kunc M, Šreibr S, Dostálková S, Petřivalský M, Hyršl P, Titěra D, Danihlík J, Dobeš P. Modeling seasonal immune dynamics of honey bee (Apis mellifera L.) response to injection of heat-killed Serratia marcescens. PLoS One 2024; 19:e0311415. [PMID: 39365765 PMCID: PMC11452037 DOI: 10.1371/journal.pone.0311415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2024] [Accepted: 09/18/2024] [Indexed: 10/06/2024] Open
Abstract
The honey bee, Apis mellifera L., is one of the main pollinators worldwide. In a temperate climate, seasonality affects the life span, behavior, physiology, and immunity of honey bees. In consequence, it impacts their interaction with pathogens and parasites. In this study, we used Bayesian statistics and modeling to examine the immune response dynamics of summer and winter honey bee workers after injection with the heat-killed bacteria Serratia marcescens, an opportunistic honey bee pathogen. We investigated the humoral and cellular immune response at the transcriptional and functional levels using qPCR of selected immune genes, antimicrobial activity assay, and flow cytometric analysis of hemocyte concentration. Our data demonstrate increased antimicrobial activity at transcriptional and functional levels in summer and winter workers after injection, with a stronger immune response in winter bees. On the other hand, an increase in hemocyte concentration was observed only in the summer bee population. Our results indicate that the summer population mounts a cellular response when challenged with heat-killed S. marcescens, while winter honey bees predominantly rely on humoral immune reactions. We created a model describing the honey bee immune response dynamics to bacteria-derived components by applying Bayesian statistics to our data. This model can be employed in further research and facilitate the investigating of the honey bee immune system and its response to pathogens.
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Affiliation(s)
- Jana Hurychová
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Jakub Dostál
- Department of Mathematical Analysis and Application of Mathematics, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - Martin Kunc
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Sara Šreibr
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Silvie Dostálková
- Department of Biochemistry, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - Marek Petřivalský
- Department of Biochemistry, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - Pavel Hyršl
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Dalibor Titěra
- Department of Zoology and Fisheries, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Science Prague, Prague, Czech Republic
| | - Jiří Danihlík
- Department of Biochemistry, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - Pavel Dobeš
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
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Wang S, Miao S, Li Y, Wang J, Li C, Lu Y, Li B. Morphological and functional characterization of circulating hemocytes in Tribolium castaneum larvae. INSECT SCIENCE 2024. [PMID: 39361781 DOI: 10.1111/1744-7917.13455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2024] [Revised: 08/15/2024] [Accepted: 08/22/2024] [Indexed: 10/05/2024]
Abstract
Hemocytes are pivotal in the immune response of insects against invasive pathogens. However, our knowledge of hemocyte types and their specific function in Tribolium castaneum, an increasingly important Coleoptera model insect in various research fields, remains limited. Presently, a combination of morphological criteria and dye-staining properties were used to characterize hemocyte types from T. castaneum larvae, and 4 distinct types were identified: granulocytes, oenocytoids, plasmatocytes and prohemocytes. Following different immune challenges, the total hemocyte counts declined rapidly in the initial phase (at 2 h), then increased over time (at 4 and 6 h) and eventually returned to the naive state by 24 h post-injection. Notably, the morphology of granulocytes underwent dramatic changes, characterized by an expansion of the surface area and an increased production of pseudopods, and with the number of granulocytes rising significantly through mitotic division. Granulocytes and plasmatocytes, the main hemocyte types in T. castaneum larvae, can phagocytose bacteria or latex beads injected into the larval hemolymph in vivo. Furthermore, these hemocytes participate in the encapsulation and melanization processes in vitro, forming capsules to encapsulate and melanize nickel-nitrilotriacetic acid (Ni-NTA) beads. This study provides the first comprehensive characterization of circulating hemocytes in T. castaneum larvae, offering valuable insights into cell-mediated immunity in response to bacterial infection and the injection of latex beads. These results deepen our understanding of the cellular response mechanisms in T. castaneum larvae and lay a solid foundation for subsequent investigations of the involvement of T. castaneum hemocytes in combating pathogens.
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Affiliation(s)
- Suisui Wang
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Shiyuan Miao
- School of Grain Science and Technology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu Province, China
- College of Environmental and Life Science, Murdoch University, Murdoch, WA, Australia
| | - Yusi Li
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Jianhui Wang
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Chengjun Li
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Yujie Lu
- School of Grain Science and Technology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu Province, China
| | - Bin Li
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
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Meier CJ, Ahmed S, Barr JS, Estévez-Lao TY, Hillyer JF. Extracellular matrix proteins Pericardin and Lonely heart mediate periostial hemocyte aggregation in the mosquito Anopheles gambiae. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2024; 159:105219. [PMID: 38925431 DOI: 10.1016/j.dci.2024.105219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Revised: 06/18/2024] [Accepted: 06/22/2024] [Indexed: 06/28/2024]
Abstract
An infection induces the migration of immune cells called hemocytes to the insect heart, where they aggregate around heart valves called ostia and phagocytose pathogens in areas of high hemolymph flow. Here, we investigated whether the cardiac extracellular matrix proteins, Pericardin (Prc) and Lonely heart (Loh), regulate the infection-induced aggregation of periostial hemocytes in the mosquito, An. gambiae. We discovered that RNAi-based post-transcriptional silencing of Prc or Loh did not affect the resident population of periostial hemocytes in uninfected mosquitoes, but that knocking down these genes decreases the infection-induced migration of hemocytes to the heart. Knocking down Prc or Loh did not affect the proportional distribution of periostial hemocytes along the periostial regions. Moreover, knocking down Prc or Loh did not affect the number of sessile hemocytes outside the periostial regions, suggesting that the role of these proteins is cardiac-specific. Finally, knocking down Prc or Loh did not affect the amount of melanin at the periostial regions, or the intensity of an infection at 24 h after challenge. Overall, we demonstrate that Prc and Loh are positive regulators of the infection-induced migration of hemocytes to the heart of mosquitoes.
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Affiliation(s)
- Cole J Meier
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Shabbir Ahmed
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Jordyn S Barr
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Tania Y Estévez-Lao
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Julián F Hillyer
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA.
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Barr JS, Martin LE, Tate AT, Hillyer JF. Warmer environmental temperature accelerates aging in mosquitoes, decreasing longevity and worsening infection outcomes. Immun Ageing 2024; 21:61. [PMID: 39261928 PMCID: PMC11389126 DOI: 10.1186/s12979-024-00465-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2024] [Accepted: 09/04/2024] [Indexed: 09/13/2024]
Abstract
BACKGROUND Most insects are poikilotherms and ectotherms, so their body temperature is predicated by environmental temperature. With climate change, insect body temperature is rising, which affects how insects develop, survive, and respond to infection. Aging also affects insect physiology by deteriorating body condition and weakening immune proficiency via senescence. Aging is usually considered in terms of time, or chronological age, but it can also be conceptualized in terms of body function, or physiological age. We hypothesized that warmer temperature decouples chronological and physiological age in insects by accelerating senescence. To investigate this, we reared the African malaria mosquito, Anopheles gambiae, at 27 °C, 30 °C and 32 °C, and measured survival starting at 1-, 5-, 10- and 15-days of adulthood after no manipulation, injury, or a hemocoelic infection with Escherichia coli or Micrococcus luteus. Then, we measured the intensity of an E. coli infection to determine how the interaction between environmental temperature and aging shapes a mosquito's response to infection. RESULTS We demonstrate that longevity declines when a mosquito is infected with bacteria, mosquitoes have shorter lifespans when the temperature is warmer, older mosquitoes are more likely to die, and warmer temperature marginally accelerates the aging-dependent decline in survival. Furthermore, we discovered that E. coli infection intensity increases when the temperature is warmer and with aging, and that warmer temperature accelerates the aging-dependent increase in infection intensity. Finally, we uncovered that warmer temperature affects both bacterial and mosquito physiology. CONCLUSIONS Warmer environmental temperature accelerates aging in mosquitoes, negatively affecting both longevity and infection outcomes. These findings have implications for how insects will serve as pollinators, agricultural pests, and disease vectors in our warming world.
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Affiliation(s)
- Jordyn S Barr
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Lindsay E Martin
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Ann T Tate
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Julián F Hillyer
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA.
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Mousavi Shafi ZS, Firouz ZM, Pirahmadi S. Gene expression analysis of Anopheles Meigen, 1818 (Diptera: Culicidae) innate immunity after Plasmodium Marchiafava & Celli, 1885 (Apicomplexa) infection: Toward developing new malaria control strategies. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2024; 123:105650. [PMID: 39089500 DOI: 10.1016/j.meegid.2024.105650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 07/27/2024] [Accepted: 07/28/2024] [Indexed: 08/04/2024]
Abstract
Despite the critical role of the Anopheles innate immune system in defending against Plasmodium infection, there is still limited information about the key immune mechanisms in Anopheles. This review assesses recent findings on the expression characteristics of immune-related genes in Anopheles following exposure to Plasmodium. A literature review, unrestricted by publication date, was conducted to evaluate immune-related gene expression in different organs of Anopheles after Plasmodium infection. Mosquito immune responses in the midgut are essential for reducing parasite populations. Additionally, innate immune responses in the salivary glands and hemocytes circulating in the hemocoel play key roles in defense against the parasite. Transcriptomic analysis of the mosquito's innate immune response to Plasmodium infection provides valuable insights into key immune mechanisms in mosquito defense. A deeper understanding of immune mechanisms in different organs of Anopheles following Plasmodium infection will aid in discovering critical targets for designing novel control strategies.
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Affiliation(s)
- Zahra Sadat Mousavi Shafi
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran
| | - Zeinab Mohammadi Firouz
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran
| | - Sakineh Pirahmadi
- Malaria and Vector Research Group (MVRG), Biotechnology Research Center (BRC), Pasteur Institute of Iran, Tehran, Iran.
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Samantsidis GR, Kwon H, Wendland M, Fonder C, Smith RC. TNF signaling mediates cellular immune function and promotes malaria parasite killing in the mosquito Anopheles gambiae. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.02.592209. [PMID: 38746363 PMCID: PMC11092648 DOI: 10.1101/2024.05.02.592209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Tumor Necrosis Factor-α (TNF-α) is a proinflammatory cytokine and a master regulator of immune cell function in vertebrates. While previous studies have implicated TNF signaling in invertebrate immunity, the roles of TNF in mosquito innate immunity and vector competence have yet to be explored. Herein, we confirm the identification of a conserved TNF-α pathway in Anopheles gambiae consisting of the TNF-α ligand, Eiger, and its cognate receptors Wengen and Grindelwald. Through gene expression analysis, RNAi, and in vivo injection of recombinant TNF-α, we provide direct evidence for the requirement of TNF signaling in regulating mosquito immune cell function by promoting granulocyte midgut attachment, increased granulocyte abundance, and oenocytoid rupture. Moreover, our data demonstrate that TNF signaling is an integral component of anti-Plasmodium immunity that limits malaria parasite survival. Together, our data support the existence of a highly conserved TNF signaling pathway in mosquitoes that mediates cellular immunity and influences Plasmodium infection outcomes, offering potential new approaches to interfere with malaria transmission by targeting the mosquito host.
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Affiliation(s)
| | - Hyeogsun Kwon
- Department of Plant Pathology, Entomology and Microbiology, Iowa State University, Ames, IA, USA
| | - Megan Wendland
- Department of Plant Pathology, Entomology and Microbiology, Iowa State University, Ames, IA, USA
| | - Catherine Fonder
- Molecular, Cellular and Developmental Biology Interdepartmental Graduate Program, Iowa State University, Ames, IA, USA
| | - Ryan C. Smith
- Department of Plant Pathology, Entomology and Microbiology, Iowa State University, Ames, IA, USA
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Hall DR, Johnson RM, Kwon H, Ferdous Z, Laredo-Tiscareño SV, Blitvich BJ, Brackney DE, Smith RC. Mosquito immune cells enhance dengue and Zika virus dissemination in Aedes aegypti. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.03.587950. [PMID: 38617257 PMCID: PMC11014501 DOI: 10.1101/2024.04.03.587950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Mosquito-borne viruses cause more than 400 million annual infections and place over half of the world's population at risk. Despite this importance, the mechanisms by which arboviruses infect the mosquito host and disseminate to tissues required for transmission are not well understood. Here, we provide evidence that mosquito immune cells, known as hemocytes, play an integral role in the dissemination of dengue virus (DENV) and Zika virus (ZIKV) in the mosquito Aedes aegypti. We establish that phagocytic hemocytes are a focal point for virus infection and demonstrate that these immune cell populations facilitate virus dissemination to the ovaries and salivary glands. Additional transfer experiments confirm that virus-infected hemocytes confer a virus infection to non-infected mosquitoes more efficiently than free virus in acellular hemolymph, revealing that hemocytes are an important tropism to enhance virus dissemination in the mosquito host. These data support a "trojan horse" model of virus dissemination where infected hemocytes transport virus through the hemolymph to deliver virus to mosquito tissues required for transmission and parallels vertebrate systems where immune cell populations promote virus dissemination to secondary sites of infection. In summary, this study significantly advances our understanding of virus infection dynamics in mosquitoes and highlights conserved roles of immune cells in virus dissemination across vertebrate and invertebrate systems.
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Affiliation(s)
- David R. Hall
- Interdepartmental Program in Genetics and Genomics, Iowa State University, Ames, Iowa
- Department of Plant Pathology, Entomology and Microbiology, Iowa State University, Ames, Iowa
| | - Rebecca M. Johnson
- Center for Vector-Borne and Zoonotic Diseases, Department of Entomology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut
| | - Hyeogsun Kwon
- Department of Plant Pathology, Entomology and Microbiology, Iowa State University, Ames, Iowa
| | - Zannatul Ferdous
- Center for Vector-Borne and Zoonotic Diseases, Department of Entomology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut
| | | | - Bradley J. Blitvich
- Department of Veterinary Microbiology and Preventative Medicine, Iowa State University, Ames, Iowa
| | - Doug E. Brackney
- Center for Vector-Borne and Zoonotic Diseases, Department of Entomology, The Connecticut Agricultural Experiment Station, New Haven, Connecticut
| | - Ryan C. Smith
- Department of Plant Pathology, Entomology and Microbiology, Iowa State University, Ames, Iowa
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Agrawal K, Prabhakar S, Bakthavachalu B, Chaturvedi D. Distinct developmental patterns in Anopheles stephensi organ systems. Dev Biol 2024; 508:107-122. [PMID: 38272285 PMCID: PMC7615899 DOI: 10.1016/j.ydbio.2024.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 01/01/2024] [Accepted: 01/16/2024] [Indexed: 01/27/2024]
Abstract
Anatomical profiles of insects inform vector biology, comparative development and evolutionary studies with applications in forensics, agriculture and disease control. This study presents a comprehensive, high-resolution developmental profile of Anopheles stephensi, encompassing larval, pupal, and adult stages, obtained through microCT scanning. The results indicate in situ anatomical changes in most organ systems, including the central nervous system, eyes, musculature, alimentary canal, salivary glands, and ovaries, among other organ systems, except for the developing heart. We find significant differences in the mosquito gut, body-wall, and flight muscle development during metamorphosis from other dipterans like Drosophila. Specifically, indirect flight muscle specification and growth can be traced back at least to the 4th instar A. stephensi larvae, as opposed to post-puparial development in other Dipterans like Drosophila and Calliphora. Further, while Drosophila larval body-wall muscles and gut undergo histolysis, changes to these organs during mosquito metamorphosis are less pronounced. These observations, and raw data therein may serve as a reference for studies on the development and the genetics of mosquitoes. Overall, the detailed developmental profile of A. stephensi presented here illuminates the unique anatomy and developmental processes of Culicidae, with important implications for vector biology, disease control, and comparative evolutionary studies.
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Affiliation(s)
- Khushboo Agrawal
- Tata Institute for Genetics and Society Centre at inStem, Bellary Road, Bangalore, 560065, India; School of Biotechnology, Amrita University, Kollam, 690525, Kerala, India
| | - Sunil Prabhakar
- Centre for Cellular and Molecular Platforms, Bellary Road, Bangalore, 560065, India
| | - Baskar Bakthavachalu
- Tata Institute for Genetics and Society Centre at inStem, Bellary Road, Bangalore, 560065, India; School of Basic Sciences, Indian Institute of Technology, Mandi, 175005, India.
| | - Dhananjay Chaturvedi
- National Centre for Biological Sciences, TIFR, Bangalore, 560065, India; CSIR - Centre for Cellular and Molecular Biology, Hyderabad, 500007, India.
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Bergmann S, Graf E, Hoffmann P, Becker SC, Stern M. Localization of nitric oxide-producing hemocytes in Aedes and Culex mosquitoes infected with bacteria. Cell Tissue Res 2024; 395:313-326. [PMID: 38240845 PMCID: PMC10904431 DOI: 10.1007/s00441-024-03862-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 01/05/2024] [Indexed: 03/01/2024]
Abstract
Mosquitoes are significant vectors of various pathogens. Unlike vertebrates, insects rely solely on innate immunity. Hemocytes play a crucial role in the cellular part of the innate immune system. The gaseous radical nitric oxide (NO) produced by hemocytes acts against pathogens and also functions as a versatile transmitter in both the immune and nervous systems, utilizing cyclic guanosine monophosphate (cGMP) as a second messenger. This study conducted a parallel comparison of NO synthase (NOS) expression and NO production in hemocytes during Escherichia coli K12 infection in four vector species: Aedes aegypti, Aedes albopictus, Culex pipiens molestus, and Culex pipiens quinquefasciatus. Increased NOS expression by NADPH diaphorase (NADPHd) staining and NO production by immunofluorescence against the by-product L-citrulline were observed in infected mosquito hemocytes distributed throughout the abdomens. NADPHd activity and citrulline labeling were particularly found in periostial hemocytes near the heart, but also on the ventral nerve chord (VNC). Pericardial cells of Ae. aegypti and Cx. p. molestus showed increased citrulline immunofluorescence, suggesting their involvement in the immune response. Oenocytes displayed strong NADPHd and citrulline labeling independent of infection status. This comparative study, consistent with findings in other species, suggests a widespread phenomenon of NO's role in hemocyte responses during E. coli infection. Found differences within and between genera highlight the importance of species-specific investigations.
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Affiliation(s)
- Stella Bergmann
- Institute for Physiology and Cell Biology, University of Veterinary Medicine Hannover, 30173, Hannover, Germany
| | - Emily Graf
- Institute for Physiology and Cell Biology, University of Veterinary Medicine Hannover, 30173, Hannover, Germany
| | - Pascal Hoffmann
- Institute for Physiology and Cell Biology, University of Veterinary Medicine Hannover, 30173, Hannover, Germany
| | - Stefanie C Becker
- Institute for Parasitology, University of Veterinary Medicine Hannover, 30559, Hannover, Germany
| | - Michael Stern
- Institute for Physiology and Cell Biology, University of Veterinary Medicine Hannover, 30173, Hannover, Germany.
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10
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Critchlow JT, Prakash A, Zhong KY, Tate AT. Mapping the functional form of the trade-off between infection resistance and reproductive fitness under dysregulated immune signaling. PLoS Pathog 2024; 20:e1012049. [PMID: 38408106 PMCID: PMC10919860 DOI: 10.1371/journal.ppat.1012049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 03/07/2024] [Accepted: 02/15/2024] [Indexed: 02/28/2024] Open
Abstract
Immune responses benefit organismal fitness by clearing parasites but also exact costs associated with immunopathology and energetic investment. Hosts manage these costs by tightly regulating the induction of immune signaling to curtail excessive responses and restore homeostasis. Despite the theoretical importance of turning off the immune response to mitigate these costs, experimentally connecting variation in the negative regulation of immune responses to organismal fitness remains a frontier in evolutionary immunology. In this study, we used a dose-response approach to manipulate the RNAi-mediated knockdown efficiency of cactus (IκBα), a central regulator of Toll pathway signal transduction in flour beetles (Tribolium castaneum). By titrating cactus activity across four distinct levels, we derived the shape of the relationship between immune response investment and traits associated with host fitness, including infection susceptibility, lifespan, fecundity, body mass, and gut homeostasis. Cactus knock-down increased the overall magnitude of inducible immune responses and delayed their resolution in a dsRNA dose-dependent manner, promoting survival and resistance following bacterial infection. However, these benefits were counterbalanced by dsRNA dose-dependent costs to lifespan, fecundity, body mass, and gut integrity. Our results allowed us to move beyond the qualitative identification of a trade-off between immune investment and fitness to actually derive its functional form. This approach paves the way to quantitatively compare the evolution and impact of distinct regulatory elements on life-history trade-offs and fitness, filling a crucial gap in our conceptual and theoretical models of immune signaling network evolution and the maintenance of natural variation in immune systems.
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Affiliation(s)
- Justin T Critchlow
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Arun Prakash
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Katherine Y Zhong
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Ann T Tate
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
- Evolutionary Studies Institute, Vanderbilt University, Nashville, Tennessee, United States of America
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11
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Martin LE, Hillyer JF. Higher temperature accelerates the aging-dependent weakening of the melanization immune response in mosquitoes. PLoS Pathog 2024; 20:e1011935. [PMID: 38198491 PMCID: PMC10805325 DOI: 10.1371/journal.ppat.1011935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/23/2024] [Accepted: 01/01/2024] [Indexed: 01/12/2024] Open
Abstract
The body temperature of mosquitoes, like most insects, is dictated by the environmental temperature. Climate change is increasing the body temperature of insects and thereby altering physiological processes such as immune proficiency. Aging also alters insect physiology, resulting in the weakening of the immune system in a process called senescence. Although both temperature and aging independently affect the immune system, it is unknown whether temperature alters the rate of immune senescence. Here, we evaluated the independent and combined effects of temperature (27°C, 30°C and 32°C) and aging (1, 5, 10 and 15 days old) on the melanization immune response of the adult female mosquito, Anopheles gambiae. Using a spectrophotometric assay that measures phenoloxidase activity (a rate limiting enzyme) in hemolymph, and therefore, the melanization potential of the mosquito, we discovered that the strength of melanization decreases with higher temperature, aging, and infection. Moreover, when the temperature is higher, the aging-dependent decline in melanization begins at a younger age. Using an optical assay that measures melanin deposition on the abdominal wall and in the periostial regions of the heart, we found that melanin is deposited after infection, that this deposition decreases with aging, and that this aging-dependent decline is accelerated by higher temperature. This study demonstrates that higher temperature accelerates immune senescence in mosquitoes, with higher temperature uncoupling physiological age from chronological age. These findings highlight the importance of investigating the consequences of climate change on how disease transmission by mosquitoes is affected by aging.
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Affiliation(s)
- Lindsay E. Martin
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Julián F. Hillyer
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
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12
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Adegoke A, Hanson J, Smith RC, Karim S. Ehrlichia chaffeensis Co-Opts Phagocytic Hemocytes for Systemic Dissemination in the Lone Star Tick, Amblyomma americanum. J Innate Immun 2023; 16:66-79. [PMID: 38142680 PMCID: PMC10794049 DOI: 10.1159/000535986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 12/20/2023] [Indexed: 12/26/2023] Open
Abstract
INTRODUCTION Hematophagous arthropods can acquire and transmit several pathogens of medical importance. In ticks, the innate immune system is crucial in the outcome between vector-pathogen interaction and overall vector competence. However, the specific immune response(s) elicited by the immune cells known as hemocytes remains largely undefined in Ehrlichia chaffeensis and its competent tick vector, Amblyomma americanum. METHODS We utilized injection of clodronate liposome to deplete tick granulocytes combined with infection with E. chaffeensis to demonstrate their essential role in microbial infection. RESULTS Here, we show that granulocytes, professional phagocytic cells, are integral in eliciting immune responses against commensal and pathogen infection. The chemical depletion of granulocytes led to decreased phagocytic efficiency of tissue-associated hemocytes. We demonstrate that E. chaffeensis can infect circulating hemocytes, and both cell-free plasma and hemocytes from E. chaffeensis-infected ticks can establish Ehrlichia infection in recipient ticks. Lastly, we provide evidence to show that granulocytes play a dual role in E. chaffeensis infection. Depleting granulocytic hemocytes increased Ehrlichia load in the salivary gland and midgut tissues. In contrast, granulocyte depletion led to a reduced systemic load of Ehrlichia. CONCLUSION This study has identified multiple roles for granulocytic hemocytes in the control and systemic dissemination of E. chaffeensis infection.
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Affiliation(s)
- Abdulsalam Adegoke
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, USA
| | - Julia Hanson
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, USA
| | - Ryan C. Smith
- Department of Plant Pathology, Entomology, and Microbiology, Iowa State University, Ames, IA, USA
| | - Shahid Karim
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, USA
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13
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Lewis J, Gallichotte EN, Randall J, Glass A, Foy BD, Ebel GD, Kading RC. Intrinsic factors driving mosquito vector competence and viral evolution: a review. Front Cell Infect Microbiol 2023; 13:1330600. [PMID: 38188633 PMCID: PMC10771300 DOI: 10.3389/fcimb.2023.1330600] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 12/08/2023] [Indexed: 01/09/2024] Open
Abstract
Mosquitoes are responsible for the transmission of numerous viruses of global health significance. The term "vector competence" describes the intrinsic ability of an arthropod vector to transmit an infectious agent. Prior to transmission, the mosquito itself presents a complex and hostile environment through which a virus must transit to ensure propagation and transmission to the next host. Viruses imbibed in an infectious blood meal must pass in and out of the mosquito midgut, traffic through the body cavity or hemocoel, invade the salivary glands, and be expelled with the saliva when the vector takes a subsequent blood meal. Viruses encounter physical, cellular, microbial, and immunological barriers, which are influenced by the genetic background of the mosquito vector as well as environmental conditions. Collectively, these factors place significant selective pressure on the virus that impact its evolution and transmission. Here, we provide an overview of the current state of the field in understanding the mosquito-specific factors that underpin vector competence and how each of these mechanisms may influence virus evolution.
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Affiliation(s)
- Juliette Lewis
- Center for Vector-borne Infectious Diseases, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Emily N. Gallichotte
- Center for Vector-borne Infectious Diseases, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Jenna Randall
- Center for Vector-borne Infectious Diseases, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Arielle Glass
- Department of Cellular and Molecular Biology, Colorado State University, Fort Collins, CO, United States
| | - Brian D. Foy
- Center for Vector-borne Infectious Diseases, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Gregory D. Ebel
- Center for Vector-borne Infectious Diseases, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Rebekah C. Kading
- Center for Vector-borne Infectious Diseases, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, United States
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14
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Dourado LA, Oliveira LL, Raimundo APP, Cossolin JFS, Oliveira JFD, Serrão JE. Hemocyte morphology of worker subcastes of the leaf-cutting ant Atta sexdens rubropilosa (Hymenoptera: Formicidae). ARTHROPOD STRUCTURE & DEVELOPMENT 2023; 76:101301. [PMID: 37660416 DOI: 10.1016/j.asd.2023.101301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 08/10/2023] [Accepted: 08/23/2023] [Indexed: 09/05/2023]
Abstract
Hemocytes are cells present in the hemolymph of insects that play a role in combating invasive pathogens, ensuring defense by the immune system in these organisms. While the types of hemocytes are well known in some insect representatives, data on these cells in Hymenoptera are limited to certain bees and wasps, with little information available for ants. Among ants, the genus Atta has environmental and economic importance, forming highly organized colonies consisting of the queen and workers, with the latter subdivided into subcastes: gardeners, waste removers, foragers, and soldiers, which are exposed to different pathogens. This study describes the morphology of hemocytes in the worker subcastes of Atta sexdens rubropilosa. Hemolymph samples from the ant were submitted to light, confocal, and scanning electron microscopy analyses. Five types of hemocytes were identified in the hemolymph of all ant subcastes, including prohemocytes, oenocytoids, spherulocytes, plasmatocytes, and granulocytes. They exhibited nuclei with a predominance of decondensed chromatin. The granulocytes were the most abundant cell type in the subcastes, followed by prohemocytes, plasmatocytes, oenocytoids, and spherulocytes. Phagocytosis assays reveal that plasmatocytes and granulocytes are the main phagocytic cells in all castes evaluated. This study fills an important gap in understanding the immune response in this ant species.
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Affiliation(s)
- Lidia Aparecida Dourado
- Department of General Biology, Instituto de Bitecnologia Aplicada à Agropecuária, Federal University of Viçosa, Viçosa, Brazil
| | - Leandro Licursi Oliveira
- Department of General Biology, Instituto de Bitecnologia Aplicada à Agropecuária, Federal University of Viçosa, Viçosa, Brazil
| | - Ana Paula Pereira Raimundo
- Department of General Biology, Instituto de Bitecnologia Aplicada à Agropecuária, Federal University of Viçosa, Viçosa, Brazil
| | - Jamile Fernanda Silva Cossolin
- Department of General Biology, Instituto de Bitecnologia Aplicada à Agropecuária, Federal University of Viçosa, Viçosa, Brazil
| | | | - José Eduardo Serrão
- Department of General Biology, Instituto de Bitecnologia Aplicada à Agropecuária, Federal University of Viçosa, Viçosa, Brazil.
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15
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Critchlow JT, Prakash A, Zhong KY, Tate AT. Mapping the functional form of the trade-off between infection resistance and reproductive fitness under dysregulated immune signaling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.10.552815. [PMID: 37645726 PMCID: PMC10461925 DOI: 10.1101/2023.08.10.552815] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Immune responses benefit organismal fitness by clearing parasites but also exact costs associated with immunopathology and energetic investment. Hosts manage these costs by tightly regulating the induction of immune signaling to curtail excessive responses and restore homeostasis. Despite the theoretical importance of turning off the immune response to mitigate these costs, experimentally connecting variation in the negative regulation of immune responses to organismal fitness remains a frontier in evolutionary immunology. In this study, we used a dose-response approach to manipulate the RNAi-mediated knockdown efficiency of cactus (IκBα), a central regulator of Toll pathway signal transduction in flour beetles (Tribolium castaneum). By titrating cactus activity along a continuous gradient, we derived the shape of the relationship between immune response investment and traits associated with host fitness, including infection susceptibility, lifespan, fecundity, body mass, and gut homeostasis. Cactus knock-down increased the overall magintude of inducible immune responses and delayed their resolution in a dsRNA dose-dependent manner, promoting survival and resistance following bacterial infection. However, these benefits were counterbalanced by dsRNA dose-dependent costs to lifespan, fecundity, body mass, and gut integrity. Our results allowed us to move beyond the qualitative identification of a trade-off between immune investment and fitness to actually derive its functional form. This approach paves the way to quantitatively compare the evolution and impact of distinct regulatory elements on life-history trade-offs and fitness, filling a crucial gap in our conceptual and theoretical models of immune signaling network evolution and the maintenance of natural variation in immune systems.
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Affiliation(s)
- Justin T. Critchlow
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Arun Prakash
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Katherine Y. Zhong
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Ann T. Tate
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
- Evolutionary Studies Institute, Vanderbilt University, Nashville, Tennessee, United States of America
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16
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Barr JS, Estevez-Lao TY, Khalif M, Saksena S, Yarlagadda S, Farah O, Shivere Y, Hillyer JF. Temperature and age, individually and interactively, shape the size, weight, and body composition of adult female mosquitoes. JOURNAL OF INSECT PHYSIOLOGY 2023; 148:104525. [PMID: 37236342 DOI: 10.1016/j.jinsphys.2023.104525] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 05/19/2023] [Accepted: 05/22/2023] [Indexed: 05/28/2023]
Abstract
Most insects are poikilotherms and ectotherms, so their body temperature fluctuates and closely aligns with the temperature of their environment. The rise in global temperatures is affecting the physiology of insects by altering their ability to survive, reproduce, and transmit disease. Aging also impacts insect physiology because the body deteriorates via senescence as the insect ages. Although temperature and age both impact insect biology, these factors have historically been studied in isolation. So, it is unknown whether or how temperature and age interact to shape insect physiology. Here, we investigated the effects of warmer temperature (27 °C, 30 °C and 32 °C), aging (1, 5, 10, and 15 days post-eclosion), and their interaction on the size and body composition of the mosquito, Anopheles gambiae. We found that warmer temperatures result in slightly smaller adult mosquitoes, as measured by abdomen and tibia length. Aging alters both abdominal length and dry weight in a manner that correlates with the increase in energetic resources and tissue remodeling that occurs after metamorphosis and the senescence-based decline that ensues later. Moreover, the carbohydrate and lipid contents of adult mosquitoes are not meaningfully affected by temperature but are altered by aging: carbohydrate content increases with age whereas lipid content increases over the first few days of adulthood and then decreases. Protein content decreases with both rising temperature and aging, and the aging-associated decrease accelerates at warmer temperatures. Altogether, temperature and age, individually and to a lesser extent interactively, shape the size and composition of adult mosquitoes.
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Affiliation(s)
- Jordyn S Barr
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Tania Y Estevez-Lao
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Marina Khalif
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Saksham Saksena
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Sagnik Yarlagadda
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Ommay Farah
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Yasmine Shivere
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Julián F Hillyer
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA.
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17
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Ratnayake OC, Chotiwan N, Saavedra-Rodriguez K, Perera R. The buzz in the field: the interaction between viruses, mosquitoes, and metabolism. Front Cell Infect Microbiol 2023; 13:1128577. [PMID: 37360524 PMCID: PMC10289420 DOI: 10.3389/fcimb.2023.1128577] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 03/24/2023] [Indexed: 06/28/2023] Open
Abstract
Among many medically important pathogens, arboviruses like dengue, Zika and chikungunya cause severe health and economic burdens especially in developing countries. These viruses are primarily vectored by mosquitoes. Having surmounted geographical barriers and threat of control strategies, these vectors continue to conquer many areas of the globe exposing more than half of the world's population to these viruses. Unfortunately, no medical interventions have been capable so far to produce successful vaccines or antivirals against many of these viruses. Thus, vector control remains the fundamental strategy to prevent disease transmission. The long-established understanding regarding the replication of these viruses is that they reshape both human and mosquito host cellular membranes upon infection for their replicative benefit. This leads to or is a result of significant alterations in lipid metabolism. Metabolism involves complex chemical reactions in the body that are essential for general physiological functions and survival of an organism. Finely tuned metabolic homeostases are maintained in healthy organisms. However, a simple stimulus like a viral infection can alter this homeostatic landscape driving considerable phenotypic change. Better comprehension of these mechanisms can serve as innovative control strategies against these vectors and viruses. Here, we review the metabolic basis of fundamental mosquito biology and virus-vector interactions. The cited work provides compelling evidence that targeting metabolism can be a paradigm shift and provide potent tools for vector control as well as tools to answer many unresolved questions and gaps in the field of arbovirology.
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Affiliation(s)
- Oshani C. Ratnayake
- Center for Vector-borne Infectious Diseases, Dept. of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Nunya Chotiwan
- Center for Vector-borne Infectious Diseases, Dept. of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
- Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Samut Prakan, Thailand
| | - Karla Saavedra-Rodriguez
- Center for Vector-borne Infectious Diseases, Dept. of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Rushika Perera
- Center for Vector-borne Infectious Diseases, Dept. of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
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18
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Ma L, Yan X, Zhou L, Wang W, Chen K, Hao C, Lu Z, Qie X. Nitric oxide synthase is required for the pea aphid's defence against bacterial infection. INSECT MOLECULAR BIOLOGY 2023; 32:187-199. [PMID: 36527288 DOI: 10.1111/imb.12823] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 12/09/2022] [Indexed: 06/17/2023]
Abstract
Compared to other insects, the pea aphid Acyrthosiphon pisum has a reduced immune system with an absence of genes coding for a lot of immunity-related molecules. Notably, nitric oxide synthase (NOS), which catalyses the synthesis of nitric oxide (NO), is present in the pea aphid. However, the role of NO in the immune system of pea aphid remains unclear. In this study, we explored the role of NO in the defence of the pea aphid against bacterial infections and found that the NOS gene of the pea aphid responded to an immune challenge, with the expression of ApNOS observably upregulated after bacterial infections. Knockdown of ApNOS using RNA interference or inhibition of NOS activity increased the number of live bacterial cells in aphids and the mortality of aphids after bacterial infection. Conversely, the increase in NO level in aphids using NO donor inhibited the bacterial growth, increased the survival of bacteria-infected aphids, and upregulated immune genes, such as Toll pathway and phagocytosis related genes. Thus, NO promotes immune responses and plays an important role in the immune system of pea aphid.
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Affiliation(s)
- Li Ma
- Department of Plant Protection, College of Plant Protection, Shanxi Agricultural University, Taigu, China
| | - Xizhong Yan
- Department of Plant Protection, College of Plant Protection, Shanxi Agricultural University, Taigu, China
| | - Lin Zhou
- Department of Entomology, College of Plant Protection, Northwest A & F University, Yangling, China
| | - Wentao Wang
- Department of Plant Protection, College of Plant Protection, Shanxi Agricultural University, Taigu, China
| | - Kangkang Chen
- Department of Plant Protection, College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China
| | - Chi Hao
- Department of Plant Protection, College of Plant Protection, Shanxi Agricultural University, Taigu, China
| | - Zhiqiang Lu
- Department of Entomology, College of Plant Protection, Northwest A & F University, Yangling, China
- Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess, Ministry of Agriculture, Northwest A & F University, Yangling, China
| | - Xingtao Qie
- Department of Plant Protection, College of Plant Protection, Shanxi Agricultural University, Taigu, China
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19
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Amaro-Sánchez T, Ruiz-Guzmán G, Hernández-Martínez S, Krams I, Rantala MJ, Contreras-Garduño J. Effect of juvenile hormone on phenoloxidase and hemocyte number: The role of age, sex, and immune challenge. Comp Biochem Physiol B Biochem Mol Biol 2023; 265:110827. [PMID: 36610635 DOI: 10.1016/j.cbpb.2023.110827] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 01/02/2023] [Accepted: 01/03/2023] [Indexed: 01/06/2023]
Abstract
Hormones are key factors in determining the response of organisms to their environment. For example, the juvenile hormone (JH) coordinates the insects' development, reproduction, and survival. However, it is still unclear how the impact of juvenile hormone on insect immunity varies depending on the sex and reproductive state of the individual, as well as the type of the immune challenge (i.e., Gram-positive or Gram-negative bacteria). We used Tenebrio molitor and methoprene, a JH analog (JHa) to explore these relationships. We tested the effect of methoprene on phenoloxidase activity (PO), an important component of humoral immunity in insects, and hemocyte number. Lyophilized Gram-positive Staphylococcus aureus or Gram-negative Escherichia coli were injected for the immune challenge. The results suggest that JH did not affect the proPO, PO activity, or hemocyte number of larvae. JH and immune challenge affected the immune response and consequently, affected adult developmental stage and sex. We propose that the influence of JH on the immune response depends on age, sex, the immune response parameter, and the immune challenge, which may explain the contrasting results about the role of JH in the insect immune response.
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Affiliation(s)
- Tania Amaro-Sánchez
- Departamento de Biología, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Campus Guanajuato, Noria Alta s/n, Colonia Noria Alta, 36050 Guanajuato, Mexico
| | - Gloria Ruiz-Guzmán
- Escuela Nacional de Estudios Superiores, Unidad Morelia, Universidad Nacional Autónoma de México, Antigua Carretera a Pátzcuaro No.8701, Col. Ex-Hacienda San José de la Huerta, 58190 Morelia, Michoacán, Mexico
| | - Salvador Hernández-Martínez
- Centro de Investigaciones sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, 62300 Cuernavaca, Morelos, Mexico
| | - Indrikis Krams
- Institute of Ecology and Earth Sciences, University of Tartu, Vanemuise 46, 51014 Tartu, Estonia; Department of Biotechnology, Daugavpils University, Daugavpils 5401, Latvia; Department of Zoology and Animal Ecology, Faculty of Biology, University of Latvia, Riga 1004, Latvia
| | - Markus J Rantala
- Department of Biology & Turku Brain and Mind Center, University of Turku, Turku, Finland
| | - Jorge Contreras-Garduño
- Escuela Nacional de Estudios Superiores, Unidad Morelia, Universidad Nacional Autónoma de México, Antigua Carretera a Pátzcuaro No.8701, Col. Ex-Hacienda San José de la Huerta, 58190 Morelia, Michoacán, Mexico.
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20
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Adegoke A, Ribeiro JMC, Brown S, Smith RC, Karim S. Rickettsia parkeri hijacks tick hemocytes to manipulate cellular and humoral transcriptional responses. Front Immunol 2023; 14:1094326. [PMID: 36845157 PMCID: PMC9950277 DOI: 10.3389/fimmu.2023.1094326] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 01/16/2023] [Indexed: 02/12/2023] Open
Abstract
Introduction Blood-feeding arthropods rely on robust cellular and humoral immunity to control pathogen invasion and replication. Tick hemocytes produce factors that can facilitate or suppress microbial infection and pathogenesis. Despite the importance of hemocytes in regulating microbial infection, understanding of their basic biology and molecular mechanisms remains limited. Methods Here we combined histomorphology and functional analysis to identify five distinct phagocytic and non-phagocytic hemocyte populations circulating within the Gulf Coast tick Amblyomma maculatum. Results and discussion Depletion of phagocytic hemocytes using clodronate liposomes revealed their function in eliminating bacterial infection. We provide the first direct evidence that an intracellular tick-borne pathogen, Rickettsia parkeri, infects phagocytic hemocytes in Am. maculatum to modify tick cellular immune responses. A hemocyte-specific RNA-seq dataset generated from hemocytes isolated from uninfected and R. parkeri-infected partially blood-fed ticks generated ~40,000 differentially regulated transcripts, >11,000 of which were immune genes. Silencing two differentially regulated phagocytic immune marker genes (nimrod B2 and eater-two Drosophila homologs), significantly reduced hemocyte phagocytosis. Conclusion Together, these findings represent a significant step forward in understanding how hemocytes regulate microbial homeostasis and vector competence.
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Affiliation(s)
- Abdulsalam Adegoke
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, United States
| | - Jose M. C. Ribeiro
- Vector Biology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, United States
| | - Sidney Brown
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, United States
| | - Ryan C. Smith
- Department of Plant Pathology, Entomology, and Microbiology, Iowa State University, Ames, IA, United States
| | - Shahid Karim
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, MS, United States
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21
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Sneed SD, Dwivedi SB, DiGate C, Denecke S, Povelones M. Aedes aegypti Malpighian tubules are immunologically activated following systemic Toll activation. Parasit Vectors 2022; 15:469. [PMID: 36522779 PMCID: PMC9753289 DOI: 10.1186/s13071-022-05567-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Accepted: 11/02/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Canine heartworm is a widespread and potentially fatal mosquito-borne disease caused by infections with the parasitic nematode, Dirofilaria immitis. We have previously shown that systemic activation of the Toll immune pathway via silencing of the negative regulator Cactus in Aedes aegypti blocks parasite development in the Malpighian tubules (MT), the mosquito renal organ. However, it was not established whether the MT were directly responding to Toll activation or were alternatively responding to upregulated proteins or other changes to the hemolymph driven by other tissues. Distinguishing these possibilities is crucial for developing more precise strategies to block D. immitis while potentially avoiding the fitness cost to the mosquito associated with Cactus silencing. METHODS This study defines the transcriptional response of the MT and changes to the hemolymph proteome of Ae. aegypti after systemic Toll activation via intra-thoracic injection of double-stranded Cactus (dsCactus) RNA. RESULTS Malpighian tubules significantly increased expression of the Toll pathway target genes that significantly overlapped expression changes occurring in whole mosquitoes. A significant overlap between the transcriptional response of the MT and proteins upregulated in the hemolymph was also observed. CONCLUSIONS Our data show that MT are capable of RNA interference-mediated gene silencing and directly respond to dsCactus treatment by upregulating targets of the canonical Toll pathway. Although not definitive, the strong correspondence between the MT transcriptional response and the hemolymph proteomic responses provides evidence that the MT may contribute to mosquito humoral immunity.
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Affiliation(s)
- Sarah D. Sneed
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104 USA
| | - Sutopa B. Dwivedi
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104 USA
| | - Cameron DiGate
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104 USA
| | - Shane Denecke
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104 USA
| | - Michael Povelones
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104 USA
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22
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Moraes RM, Garcia MT, Stossi F, de Barros PP, Junqueira JC, Anbinder AL. Effects of α and β-adrenergic signaling on innate immunity and Porphyromonas gingivalis virulence in an invertebrate model. Virulence 2022; 13:1614-1630. [PMID: 36121102 PMCID: PMC9487758 DOI: 10.1080/21505594.2022.2123302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
To investigate the role of adrenergic signalling (AS) in the host immune response and Porphyromonas gingivalis virulence, we compared norepinephrine (NE) and isoproterenol (ISO) responses in Galleria mellonella. P. gingivalis infection was evaluated by survival; humoral immune responses (i.e. melanization and cecropin and gloverin mRNA expression); cellular immune responses (i.e. haemocyte count, nodulation by histology); and P. gingivalis recovery (CFU/mL). P. gingivalis was cultivated in the presence of ISO (PgISO) or NE and injected into the larvae for survival evaluation. Finally, we co-injected ISO and PgISO to evaluate the concomitant effects on the immune response and bacterial virulence. None of the ligands were toxic to the larvae; ISO increased haemocyte number, even after P. gingivalis infection, by mobilizing sessile haemocytes in a β-adrenergic-specific manner, while NE showed the opposite effect. ISO treatment reduced larval mortality and the number of recovered bacteria, while NE increased mortality and showed no effect on bacterial recovery. ISO and NE had similar effects on melanization and decreased the expression of cecropin. Although co-cultivation with NE and ISO increased the gene expression of bacterial virulence factors in vitro, only the injection of PgISO increased larval death, which was partially reversed by circulating ISO. Therefore, α- and β-adrenergic signalling had opposite effects after P. gingivalis infection. Ultimately, the catecholamine influence on the immune response overcame the effect of more virulent strains. The effect of AS directly on the pathogen found in vitro did not translate to the in vivo setting.
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Affiliation(s)
- Renata Mendonça Moraes
- Institute of Science and Technology, Biosciences and Diagnosis Department, São Paulo State University (Unesp), São José dos Campos, SP, Brazil
| | - Maíra Terra Garcia
- Institute of Science and Technology, Biosciences and Diagnosis Department, São Paulo State University (Unesp), São José dos Campos, SP, Brazil
| | - Fabio Stossi
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA.,GCC Center for Advanced Microscopy and Image Informatics, Houston, Texas, USA
| | - Patrícia Pimentel de Barros
- Institute of Science and Technology, Biosciences and Diagnosis Department, São Paulo State University (Unesp), São José dos Campos, SP, Brazil.,Multicampi School of Medical Sciences, Federal University of Rio Grande do Norte (UFRN), Caicó, RN, Brazil
| | - Juliana Campos Junqueira
- Institute of Science and Technology, Biosciences and Diagnosis Department, São Paulo State University (Unesp), São José dos Campos, SP, Brazil
| | - Ana Lia Anbinder
- Institute of Science and Technology, Biosciences and Diagnosis Department, São Paulo State University (Unesp), São José dos Campos, SP, Brazil
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23
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Adegoke A, Kumar D, Budachetri K, Karim S. Hematophagy and tick-borne Rickettsial pathogen shape the microbial community structure and predicted functions within the tick vector, Amblyomma maculatum. Front Cell Infect Microbiol 2022; 12:1037387. [PMID: 36478675 PMCID: PMC9719966 DOI: 10.3389/fcimb.2022.1037387] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 11/03/2022] [Indexed: 11/22/2022] Open
Abstract
Background Ticks are the primary vectors of emerging and resurging pathogens of public health significance worldwide. Analyzing tick bacterial composition, diversity, and functionality across developmental stages and tissues is crucial for designing new strategies to control ticks and prevent tick-borne diseases. Materials and methods Here, we explored the microbial communities across the developmental timeline and in different tissues of the Gulf-Coast ticks (Amblyomma maculatum). Using a high-throughput sequencing approach, the influence of blood meal and Rickettsia parkeri, a spotted fever group rickettsiae infection in driving changes in microbiome composition, diversity, and functionality was determined. Results This study shows that the core microbiome of Am. maculatum comprises ten core bacterial genera. The genus Rickettsia, Francisella, and Candidatus_Midichloria are the key players, with positive interactions within each developmental stage and adult tick organ tested. Blood meal and Rickettsia parkeri led to an increase in the bacterial abundance in the tissues. According to functional analysis, the increase in bacterial numbers is positively correlated to highly abundant energy metabolism orthologs with blood meal. Correlation analysis identified an increase in OTUs identified as Candidatus Midichloria and a subsequent decrease in Francisella OTUs in Rickettsia parkeri infected tick stages and tissues. Results demonstrate the abundance of Rickettsia and Francisella predominate in the core microbiome of Am. maculatum, whereas Candidatus_Midichloria and Cutibacterium prevalence increase with R. parkeri-infection. Network analysis and functional annotation suggest that R. parkeri interacts positively with Candidatus_Midichloria and negatively with Francisella. Conclusion We conclude that tick-transmitted pathogens, such as R. parkeri establishes infection by interacting with the core microbiome of the tick vector.
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Affiliation(s)
- Abdulsalam Adegoke
- School of Biological, Environmental, and Earth Sciences, University of Southern Mississippi, Hattiesburg, MS, United States
| | - Deepak Kumar
- School of Biological, Environmental, and Earth Sciences, University of Southern Mississippi, Hattiesburg, MS, United States
| | - Khemraj Budachetri
- School of Biological, Environmental, and Earth Sciences, University of Southern Mississippi, Hattiesburg, MS, United States
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, United States
| | - Shahid Karim
- School of Biological, Environmental, and Earth Sciences, University of Southern Mississippi, Hattiesburg, MS, United States
- Center for Molecular and Cellular Biosciences, University of Southern Mississippi, Hattiesburg, MS, United States
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Immune defense mechanisms against a systemic bacterial infection in the cat flea (Ctenocephalides felis). J Invertebr Pathol 2022; 195:107850. [DOI: 10.1016/j.jip.2022.107850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 10/14/2022] [Accepted: 11/01/2022] [Indexed: 11/06/2022]
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Cardoso-Jaime V, Tikhe CV, Dong S, Dimopoulos G. The Role of Mosquito Hemocytes in Viral Infections. Viruses 2022; 14:v14102088. [PMID: 36298644 PMCID: PMC9608948 DOI: 10.3390/v14102088] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 09/03/2022] [Accepted: 09/13/2022] [Indexed: 11/16/2022] Open
Abstract
Insect hemocytes are the only immune cells that can mount a humoral and cellular immune response. Despite the critical involvement of hemocytes in immune responses against bacteria, fungi, and parasites in mosquitoes, our understanding of their antiviral potential is still limited. It has been shown that hemocytes express humoral factors such as TEP1, PPO, and certain antimicrobial peptides that are known to restrict viral infections. Insect hemocytes also harbor the major immune pathways, such as JAK/STAT, TOLL, IMD, and RNAi, which are critical for the control of viral infection. Recent research has indicated a role for hemocytes in the regulation of viral infection through RNA interference and autophagy; however, the specific mechanism by which this regulation occurs remains uncharacterized. Conversely, some studies have suggested that hemocytes act as agonists of arboviral infection because they lack basal lamina and circulate throughout the whole mosquito, likely facilitating viral dissemination to other tissues such as salivary glands. In addition, hemocytes produce arbovirus agonist factors such as lectins, which enhance viral infection. Here, we summarize our current understanding of hemocytes’ involvement in viral infections.
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26
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Yan Y, Sigle LT, Rinker DC, Estévez-Lao TY, Capra JA, Hillyer JF. The immune deficiency and c-Jun N-terminal kinase pathways drive the functional integration of the immune and circulatory systems of mosquitoes. Open Biol 2022; 12:220111. [PMID: 36069078 PMCID: PMC9449813 DOI: 10.1098/rsob.220111] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The immune and circulatory systems of animals are functionally integrated. In mammals, the spleen and lymph nodes filter and destroy microbes circulating in the blood and lymph, respectively. In insects, immune cells that surround the heart valves (ostia), called periostial haemocytes, destroy pathogens in the areas of the body that experience the swiftest haemolymph (blood) flow. An infection recruits additional periostial haemocytes, amplifying heart-associated immune responses. Although the structural mechanics of periostial haemocyte aggregation have been defined, the genetic factors that regulate this process remain less understood. Here, we conducted RNA sequencing in the African malaria mosquito, Anopheles gambiae, and discovered that an infection upregulates multiple components of the immune deficiency (IMD) and c-Jun N-terminal kinase (JNK) pathways in the heart with periostial haemocytes. This upregulation is greater in the heart with periostial haemocytes than in the circulating haemocytes or the entire abdomen. RNA interference-based knockdown then showed that the IMD and JNK pathways drive periostial haemocyte aggregation and alter phagocytosis and melanization on the heart, thereby demonstrating that these pathways regulate the functional integration between the immune and circulatory systems. Understanding how insects fight infection lays the foundation for novel strategies that could protect beneficial insects and harm detrimental ones.
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Affiliation(s)
- Yan Yan
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Leah T. Sigle
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - David C. Rinker
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | | | - John A. Capra
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA,Bakar Computational Health Sciences Institute and Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, USA
| | - Julián F. Hillyer
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
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von Bredow YM, Müller A, Popp PF, Iliasov D, von Bredow CR. Characterization and mode of action analysis of black soldier fly (Hermetia illucens) larva-derived hemocytes. INSECT SCIENCE 2022; 29:1071-1095. [PMID: 34687131 DOI: 10.1111/1744-7917.12977] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 10/01/2021] [Accepted: 10/04/2021] [Indexed: 06/13/2023]
Abstract
With the growing importance of the black soldier fly (Hermetia illucens) for both sustainable food production and waste management as well as for science, a great demand of understanding its immune system arises. Here, we present the first description of the circulating larval hemocytes with special emphasis on uptake of microorganisms and distinguishing hemocyte types. With histological, zymographic, and cytometric methods and with a set of hemocyte binding lectins and antibodies, the hemocytes of H. illucens are identified as plasmatocytes, crystal cells, and putative prohemocytes. Total hemocyte counts (THC) are determined, and methods for THC determination are compared. Approximately 1100 hemocytes per microliter hemolymph are present in naive animals, while hemocyte density decreases dramatically shortly after wounding, indicating a role of hemocytes in response to wounding (and immune response in general). The determination of the relative abundance of each hemocyte type (differential hemocyte count, DHC) revealed that plasmatocytes are highly abundant, whereas prohemocytes and crystal cells make up only a small percentage of the circulating cells. Plasmatocytes are not only the most abundant but also the professional phagocytes in H. illucens. They rapidly engulf and take up bacteria both in vivo and in vitro, indicating a very potent cellular defense against invading pathogens. Larger bioparticles such as yeasts are also removed from circulation by phagocytosis, but slower than bacteria. This is the first analysis of the potent cellular immune response in the black soldier fly, and a first toolbox that helps to identify hemocyte (types) is presented.
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Affiliation(s)
- Yvette M von Bredow
- Justus-Liebig-Universität Gießen, Institut für Allgemeine Zoologie und Entwicklungsbiologie, Zelluläre Erkennungs- und Abwehrprozesse, Gießen, Germany
| | - Ariane Müller
- Technische Universität Dresden, Fakultät Biologie, Institut für Zoologie, Dresden, Germany
| | - Philipp F Popp
- Technische Universität Dresden, Fakultät Biologie, Institut für Mikrobiologie, Dresden, Germany
- Present address: Philipp F. Popp, Institute for Biology-Bacterial Physiology, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Denis Iliasov
- Technische Universität Dresden, Fakultät Biologie, Institut für Mikrobiologie, Dresden, Germany
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Ramakrishnan A, Hillyer JF. Silencing Transglutaminase Genes TGase2 and TGase3 Has Infection-Dependent Effects on the Heart Rate of the Mosquito Anopheles gambiae. INSECTS 2022; 13:582. [PMID: 35886758 PMCID: PMC9315499 DOI: 10.3390/insects13070582] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 06/18/2022] [Accepted: 06/22/2022] [Indexed: 02/04/2023]
Abstract
Transglutaminases are pleiotropic enzymes that in mosquitoes participate in the formation of the mating plug and the wound-induced antimalarial response. Moreover, one transglutaminase, TGase3, negatively regulates the infection-induced aggregation of hemocytes on the heart. Given that TGase3 is an inhibitor of periostial hemocyte aggregation, we used RNAi-based gene silencing followed by intravital video imaging to scrutinize whether any of the three transglutaminases encoded in the genome of the mosquito, Anopheles gambiae, play a role in modulating the heart rate of uninfected and infected mosquitoes. Initially, we confirmed that an infection decreases the heart rate. Then, we uncovered that silencing TGase1 does not impact heart physiology, but silencing TGase2 results in a constant heart rate regardless of infection status, eliminating the infection-induced decrease in the heart rate. Finally, silencing TGase3 decreases the heart rate in uninfected mosquitoes but increases the heart rate in infected mosquitoes. We conclude that TGase2 and TGase3 modulate heart physiology and demonstrate that factors not classically associated with insect circulatory physiology are involved in the functional integration of the immune and circulatory systems of mosquitoes.
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Affiliation(s)
| | - Julián F. Hillyer
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA;
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29
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Yan Y, Ramakrishnan A, Estévez-Lao TY, Hillyer JF. Transglutaminase 3 negatively regulates immune responses on the heart of the mosquito, Anopheles gambiae. Sci Rep 2022; 12:6715. [PMID: 35468918 PMCID: PMC9038791 DOI: 10.1038/s41598-022-10766-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 04/04/2022] [Indexed: 11/09/2022] Open
Abstract
The immune and circulatory systems of insects are functionally integrated. Following infection, immune cells called hemocytes aggregate around the ostia (valves) of the heart. An earlier RNA sequencing project in the African malaria mosquito, Anopheles gambiae, revealed that the heart-associated hemocytes, called periostial hemocytes, express transglutaminases more highly than hemocytes elsewhere in the body. Here, we further queried the expression of these transglutaminase genes and examined whether they play a role in heart-associated immune responses. We found that, in the whole body, injury upregulates the expression of TGase2, whereas infection upregulates TGase1, TGase2 and TGase3. RNAi-based knockdown of TGase1 and TGase2 did not alter periostial hemocyte aggregation, but knockdown of TGase3 increased the number of periostial hemocytes during the early stages of infection and the sequestration of melanin by periostial hemocytes during the later stages of infection. In uninfected mosquitoes, knockdown of TGase3 also slightly reduced the number of sessile hemocytes outside of the periostial regions. Taken altogether, these data show that TGase3 negatively regulates periostial hemocyte aggregation, and we hypothesize that this occurs by negatively regulating the immune deficiency pathway and by altering hemocyte adhesion. In conclusion, TGase3 is involved in the functional integration between the immune and circulatory systems of mosquitoes.
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30
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Cheng L, Liu WL, Su MP, Huang SC, Wang JR, Chen CH. Prohemocytes are the main cells infected by dengue virus in Aedes aegypti and Aedes albopictus. Parasit Vectors 2022; 15:137. [PMID: 35449113 PMCID: PMC9027048 DOI: 10.1186/s13071-022-05276-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 04/06/2022] [Indexed: 11/30/2022] Open
Abstract
Background The primary disease vectors for dengue virus (DENV) transmission between humans are the mosquitoes Aedes aegypti and Aedes albopictus, with Ae. aegypti population size strongly correlated with DENV outbreaks. When a mosquito is infected with DENV, the virus migrates from the midgut to the salivary glands to complete the transmission cycle. How the virus crosses the hemocoel, resulting in systemic infection, is still unclear however. During viral infection and migration, the innate immune system is activated in defense. As part of cellular-mediated immunity, hemocytes are known to defend against bacteria and Plasmodium infection and may also participate in defending against DENV infection. Hemocytes are categorized into three cell types: prohemocytes, granulocytes, and oenocytoids. Here, we investigated which hemocytes can be infected by DENV and compare hemocyte infection between Ae. aegypti and Ae. albopictus. Methods Hemocytes were collected from Ae. aegypti and Ae. albopictus mosquitoes that were intrathoracically infected with DENV2-GFP. The collected hemocytes were then identified via Giemsa staining and examined microscopically for morphological differences and viral infection. Results All three types of hemocytes were infected by DENV, though the predominantly infected cell type was prohemocytes. In Ae. aegypti, the highest and lowest infection rates at 7 days post infection occurred in prohemocytes and granulocytes, respectively. Prohemocytes were also the primary infection target of DENV in Ae. albopictus, with similar infection rates across the other two hemocyte groups. The ratios of hemocyte composition did not differ significantly between non-infected and infected mosquitoes for either species. Conclusions In this study, we showed that prohemocytes were the major type of hemocyte infected by DENV in both Ae. aegypti and Ae. albopictus. The infection rate of prohemocytes in Ae. albopictus was lower than that in Ae. aegypti, which may explain why systemic DENV infection in Ae. albopictus is less efficient than in Ae. aegypti and why Ae. albopictus is less correlated to dengue fever outbreaks. Future work in understanding the mechanisms behind these phenomena may help reduce arbovirus infection prevalence. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-022-05276-w.
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Affiliation(s)
- Lie Cheng
- National Mosquito-Borne Diseases Control Research Center, National Health Research Institutes, Miaoli County, Taiwan
| | - Wei-Liang Liu
- National Mosquito-Borne Diseases Control Research Center, National Health Research Institutes, Miaoli County, Taiwan
| | - Matthew P Su
- Institute of Advanced Research, Nagoya University, Nagoya, Japan.,Department of Biological Science, Nagoya University, Nagoya, Japan
| | - Shu-Chen Huang
- National Mosquito-Borne Diseases Control Research Center, National Health Research Institutes, Miaoli County, Taiwan
| | - Jen-Ren Wang
- Department of Medical Laboratory Science and Biotechnology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli County, Taiwan
| | - Chun-Hong Chen
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Miaoli County, Taiwan.
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31
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Martinson EO, Chen K, Valzania L, Brown MR, Strand MR. Insulin-like peptide 3 stimulates hemocytes to proliferate in anautogenous and facultatively autogenous mosquitoes. J Exp Biol 2022; 225:274275. [PMID: 35129195 PMCID: PMC8976944 DOI: 10.1242/jeb.243460] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 01/31/2022] [Indexed: 11/20/2022]
Abstract
Most mosquito species are anautogenous, which means they must blood feed on a vertebrate host to produce eggs, while a few are autogenous and can produce eggs without blood feeding. Egg formation is best understood in the anautogenous mosquito Aedes aegypti, where insulin-like peptides (ILPs), ovary ecdysteroidogenic hormone (OEH) and 20-hydroxyecdysone (20E) interact to regulate gonadotrophic cycles. Circulating hemocytes also approximately double in abundance in conjunction with a gonadotrophic cycle, but the factors responsible for stimulating this increase remain unclear. Focusing on Ae. aegypti, we determined that hemocyte abundance similarly increased in intact blood-fed females and decapitated blood-fed females that were injected with ILP3, whereas OEH, 20E or heat-killed bacteria had no stimulatory activity. ILP3 upregulated insulin-insulin growth factor signaling in hemocytes, but few genes - including almost no transcripts for immune factors - were differentially expressed. ILP3 also stimulated circulating hemocytes to increase in two other anautogenous (Anopheles gambiae and Culex quinquefasciatus) and two facultatively autogenous mosquitoes (Aedes atropalpus and Culex pipiens molestus), but had no stimulatory activity in the obligately autogenous mosquito Toxorhynchites amboinensis. Altogether, our results identify ILPs as the primary regulators of hemocyte proliferation in association with egg formation, but also suggest this response has been lost in the evolution of obligate autogeny.
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Affiliation(s)
- Ellen O Martinson
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
| | - Kangkang Chen
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
| | - Luca Valzania
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
| | - Mark R Brown
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
| | - Michael R Strand
- Department of Entomology, University of Georgia, Athens, GA 30602, USA
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Variation of TNF modulates cellular immunity of gregarious and solitary locusts against fungal pathogen Metarhizium anisopliae. Proc Natl Acad Sci U S A 2022; 119:2120835119. [PMID: 35110413 PMCID: PMC8833202 DOI: 10.1073/pnas.2120835119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/28/2021] [Indexed: 12/11/2022] Open
Abstract
Ecological immunology addresses the interactions between host immunity and the environment. Locusts display density-dependent phase transitions between solitary and gregarious locusts. In control practices and laboratory bioassays, gregarious locusts always exhibit stronger resistance to fungal pathogens than solitary locusts. However, few studies have investigated the mechanism of altered immune switch in locusts. Here, we combined mathematical simulation and experimental studies to show that gregarious locusts inhibit tumor necrosis factor (TNF) to alter immune defense by enhancing humoral defense and reducing cellular defense, and high levels of TNF reduce the survival of solitary locusts. Our study provides an important cue for understanding cellular immunity variations in response to different population densities and for improving the control efficacy of locust plagues. Changes in population density lead to phenotypic differentiation of solitary and gregarious locusts, which display different resistance to fungal pathogens; however, how to regulate their cellular immune strategies remains unknown. Here, our stochastic simulation of pathogen proliferation suggested that humoral defense always enhanced resistance to fungal pathogens, while phagocytosis sometimes reduced defense against pathogens. Further experimental data proved that gregarious locusts had significantly decreased phagocytosis of hemocytes compared to solitary locusts. Additionally, transcriptional analysis showed that gregarious locusts promoted immune effector expression (gnbp1 and dfp) and reduced phagocytic gene expression (eater) and the cytokine tumor necrosis factor (TNF). Interestingly, higher expression of the cytokine TNF in solitary locusts simultaneously promoted eater expression and inhibited gnbp1 and dfp expression. Moreover, inhibition of TNF increased the survival of solitary locusts, and injection of TNF decreased the survival of gregarious locusts after fungal infection. Therefore, our results indicate that the alerted expression of TNF regulated the immune strategy of locusts to adapt to environmental changes.
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Rapid regulation of hemocyte homeostasis in crayfish and its manipulation by viral infection. FISH AND SHELLFISH IMMUNOLOGY REPORTS 2021; 2:100035. [DOI: 10.1016/j.fsirep.2021.100035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/30/2021] [Accepted: 11/05/2021] [Indexed: 12/16/2022] Open
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Meraj S, Mohr E, Ketabchi N, Bogdanovic A, Lowenberger C, Gries G. Time- and tissue-specific antimicrobial activity of the common bed bug in response to blood feeding and immune activation by bacterial injection. JOURNAL OF INSECT PHYSIOLOGY 2021; 135:104322. [PMID: 34644597 DOI: 10.1016/j.jinsphys.2021.104322] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 09/16/2021] [Accepted: 10/05/2021] [Indexed: 06/13/2023]
Abstract
Unlike almost all hematophagous insects, common bed bugs, Cimex lectularius, are not known to transmit pathogens to humans. To help unravel the reasons for their lack of vector competence, we studied the time- and tissue-dependent expression of innate immune factors after blood feeding or immune activation through the intrathoracic injection of bacteria. We used minimum inhibitory concentration (MIC1) bioassays and the Kirby-Bauer protocol to evaluate antimicrobial peptide (AMP2) activity in tissue extracts from the midguts or 'rest of body' (RoB3) tissues (containing hemolymph and fat body AMPs) against Gram-positive and Gram-negative bacteria. We compared AMP activity between blood-fed female bed bugs and yellow fever mosquitoes, Aedes aegypti and determined how female and male bed bugs respond to immune challenges, and how long AMP gene expression remains elevated in bed bugs following a blood meal. Blood meal-induced AMP activity is 4-fold stronger in female bed bugs than in female mosquitoes. Male bed bugs have elevated AMP activity within 8 h of a blood meal or an intrathoracic injection with bacteria, with the strongest activity expressed in RoB tissue 24 h after the immune challenge. Female bed bugs have a stronger immune response than males within 24 h of a blood meal. The effects of blood meal-induced elevated AMP activity lasts longer against the Gram-positive bacterium, Bacillus subtilis, than against the Gram-negative bacterium Escherichia coli. Unravelling the specific immune pathways that are activated in the bed bugs' immune responses and identifying the bed bug-unique AMPs might help determine why these insects are not vectors of human parasites.
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Affiliation(s)
- Sanam Meraj
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia V5A1S6, Canada.
| | - Emerson Mohr
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia V5A1S6, Canada
| | - Negin Ketabchi
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia V5A1S6, Canada
| | - Anastasia Bogdanovic
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia V5A1S6, Canada
| | - Carl Lowenberger
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia V5A1S6, Canada
| | - Gerhard Gries
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia V5A1S6, Canada
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NO Synthesis in Immune-Challenged Locust Hemocytes and Potential Signaling to the CNS. INSECTS 2021; 12:insects12100951. [PMID: 34680720 PMCID: PMC8539611 DOI: 10.3390/insects12100951] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/13/2021] [Accepted: 10/15/2021] [Indexed: 01/22/2023]
Abstract
Simple Summary Insects, in the same way as vertebrates, are exposed to a broad variety of pathogens but lack their adaptive immune system. Relying on their innate immune system, they respond to pathogens by phagocytosis, melanization, and the synthesis of antimicrobial or cytotoxic compounds. In this study, we evaluated the production of the cytotoxic gaseous radical nitric oxide (NO) in hemocytes, the immune cells of the model insect Locusta migratoria in response to various immune stimuli. Both sessile and circulating hemocytes responded to gram-negative Escherichia coli and gram-positive Streptococcus suis injection with a strong increase in NO production. In contrast, the gram-positive bacterium Staphylococcus aureus elicited only a minor response. In addition, bacteria were encapsulated by hemocytes. Since NO is an important neurotransmitter, NO-producing hemocytes were tested on the locust central nervous system (CNS) in an embryo culture model. CNS neurons responded with a distinct increase in production of the second messenger, cGMP. This is indicative of the influence of the immune response on the CNS. Our findings show that NO production in hemocytes and capsule formation need complex stimuli and contribute to the understanding of neuroimmune interactions in insects. Abstract Similar to vertebrates, insects are exposed to a broad variety of pathogens. The innate insect immune system provides several response mechanisms such as phagocytosis, melanization, and the synthesis of antimicrobial or cytotoxic compounds. The cytotoxic nitric oxide (NO), which is also a neurotransmitter, is involved in the response to bacterial infections in various insects but has rarely been shown to be actually produced in hemocytes. We quantified the NO production in hemocytes of Locusta migratoria challenged with diverse immune stimuli by immunolabeling the by-product of NO synthesis, citrulline. Whereas in untreated adult locusts less than 5% of circulating hemocytes were citrulline-positive, the proportion rose to over 40% after 24 hours post injection of heat-inactivated bacteria. Hemocytes surrounded and melanized bacteria in locust nymphs by forming capsules. Such sessile hemocytes also produced NO. As in other insect species, activated hemocytes were found dorsally, close to the heart. In addition, we frequently observed citrulline-positive hemocytes and capsules near the ventral nerve cord. Neurites in the CNS of sterile locust embryos responded with elevation of the second messenger cGMP after contact with purified adult NO-producing hemocytes as revealed by immunofluorescence. We suggest that hemocytes can mediate a response in the CNS of an infected animal via the NO/cGMP signaling pathway.
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Kwon H, Mohammed M, Franzén O, Ankarklev J, Smith RC. Single-cell analysis of mosquito hemocytes identifies signatures of immune cell subtypes and cell differentiation. eLife 2021; 10:66192. [PMID: 34318744 PMCID: PMC8376254 DOI: 10.7554/elife.66192] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Accepted: 07/27/2021] [Indexed: 12/16/2022] Open
Abstract
Mosquito immune cells, known as hemocytes, are integral to cellular and humoral responses that limit pathogen survival and mediate immune priming. However, without reliable cell markers and genetic tools, studies of mosquito immune cells have been limited to morphological observations, leaving several aspects of their biology uncharacterized. Here, we use single-cell RNA sequencing (scRNA-seq) to characterize mosquito immune cells, demonstrating an increased complexity to previously defined prohemocyte, oenocytoid, and granulocyte subtypes. Through functional assays relying on phagocytosis, phagocyte depletion, and RNA-FISH experiments, we define markers to accurately distinguish immune cell subtypes and provide evidence for immune cell maturation and differentiation. In addition, gene-silencing experiments demonstrate the importance of lozenge in defining the mosquito oenocytoid cell fate. Together, our scRNA-seq analysis provides an important foundation for future studies of mosquito immune cell biology and a valuable resource for comparative invertebrate immunology.
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Affiliation(s)
- Hyeogsun Kwon
- Department of Entomology, Iowa State University, Ames, United States
| | - Mubasher Mohammed
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Oscar Franzén
- Integrated Cardio Metabolic Centre, Department of Medicine, Karolinska Institutet, Novum, Huddinge, Sweden
| | - Johan Ankarklev
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden.,Microbial Single Cell Genomics facility, SciLifeLab, Biomedical Center (BMC) Uppsala University, Uppsala, Sweden
| | - Ryan C Smith
- Department of Entomology, Iowa State University, Ames, United States
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Rani J, Chauhan C, Das De T, Kumari S, Sharma P, Tevatiya S, Patel K, Mishra AK, Pandey KC, Singh N, Dixit R. Hemocyte RNA-Seq analysis of Indian malarial vectors Anopheles stephensi and Anopheles culicifacies: From similarities to differences. Gene 2021; 798:145810. [PMID: 34224830 DOI: 10.1016/j.gene.2021.145810] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 06/26/2021] [Accepted: 06/30/2021] [Indexed: 02/05/2023]
Abstract
Anopheles stephensi and Anopheles culicifacies are dominant malarial vectors in urban and rural India, respectively. Both species carry significant biological differences in their behavioral adaptation and immunity, but the genetic basis of these variations are still poorly understood. Here, we uncovered the genetic differences of immune blood cells, that influence several immune-physiological responses. We generated, analyzed and compared the hemocyte RNA-Seq database of both mosquitoes. A total of 5,837,223,769 assembled bases collapsed into 7,595 and 3,791 transcripts, originating from hemocytes of laboratory-reared 3-4 days old naïve (sugar-fed) mosquitoes, Anopheles stephensi and Anopheles culicifacies respectively. Comparative GO annotation analysis revealed that both mosquito hemocytes encode similar proteins. Furthermore, while An. stephensi hemocytes showed a higher percentage of immune transcripts encoding APHAG (Autophagy), IMD (Immune deficiency pathway), PRDX (Peroxiredoxin), SCR (Scavenger receptor), IAP (Inhibitor of apoptosis), GALE (galactoside binding lectins), BGBPs (1,3 beta D glucan binding proteins), CASPs (caspases) and SRRP (Small RNA regulatory pathway), An. culicifacies hemocytes yielded a relatively higher percentage of transcripts encoding CLIP (Clip domain serine protease), FREP (Fibrinogen related proteins), PPO (Prophenol oxidase), SRPN (Serpines), ML (Myeloid differentiation 2-related lipid recognition protein), Toll path and TEP (Thioester protein), family proteins. However, a detailed comparative Interproscan analysis showed An. stephensi mosquito hemocytes encode proteins with increased repeat numbers as compared to An. culicifacies. Notably, we observed an abundance of transcripts showing significant variability of encoded proteins with repeats such as LRR (Leucine rich repeat), WD40 (W-D dipeptide), Ankyrin, Annexin, Tetratricopeptide and Mitochondrial substrate carrier repeat-containing family proteins, which may have a direct influence on species-specific immune-physiological responses. Summarily, our deep sequencing analysis unraveled that An. stephensi evolved with an expansion of repeat sequences in hemocyte proteins as compared to An. culicifacies, possibly providing an advantage for better adaptation to diverse environments.
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Affiliation(s)
- Jyoti Rani
- Laboratory of Host-Parasite Interaction Studies, ICMR-National Institute of Malaria, Research, Dwarka, New Delhi 110077, India; Department of Bio and Nanotechnology, Guru Jambheshwar University of Science and Technology, Hisar, Haryana, India
| | - Charu Chauhan
- Laboratory of Host-Parasite Interaction Studies, ICMR-National Institute of Malaria, Research, Dwarka, New Delhi 110077, India
| | - Tanwee Das De
- Laboratory of Host-Parasite Interaction Studies, ICMR-National Institute of Malaria, Research, Dwarka, New Delhi 110077, India
| | - Seena Kumari
- Laboratory of Host-Parasite Interaction Studies, ICMR-National Institute of Malaria, Research, Dwarka, New Delhi 110077, India
| | - Punita Sharma
- Laboratory of Host-Parasite Interaction Studies, ICMR-National Institute of Malaria, Research, Dwarka, New Delhi 110077, India
| | - Sanjay Tevatiya
- Laboratory of Host-Parasite Interaction Studies, ICMR-National Institute of Malaria, Research, Dwarka, New Delhi 110077, India
| | - Karan Patel
- DNA Xperts Private Limited, Sector 63, Noida, Uttar Pradesh 20130, India
| | - Ashwani K Mishra
- DNA Xperts Private Limited, Sector 63, Noida, Uttar Pradesh 20130, India
| | - Kailash C Pandey
- Laboratory of Host-Parasite Interaction Studies, ICMR-National Institute of Malaria, Research, Dwarka, New Delhi 110077, India
| | - Namita Singh
- Department of Bio and Nanotechnology, Guru Jambheshwar University of Science and Technology, Hisar, Haryana, India
| | - Rajnikant Dixit
- Laboratory of Host-Parasite Interaction Studies, ICMR-National Institute of Malaria, Research, Dwarka, New Delhi 110077, India.
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Leite THJF, Ferreira ÁGA, Imler JL, Marques JT. Distinct Roles of Hemocytes at Different Stages of Infection by Dengue and Zika Viruses in Aedes aegypti Mosquitoes. Front Immunol 2021; 12:660873. [PMID: 34093550 PMCID: PMC8169962 DOI: 10.3389/fimmu.2021.660873] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 04/30/2021] [Indexed: 12/21/2022] Open
Abstract
Aedes aegypti mosquitoes are vectors for arboviruses of medical importance such as dengue (DENV) and Zika (ZIKV) viruses. Different innate immune pathways contribute to the control of arboviruses in the mosquito vector including RNA interference, Toll and Jak-STAT pathways. However, the role of cellular responses mediated by circulating macrophage-like cells known as hemocytes remains unclear. Here we show that hemocytes are recruited to the midgut of Ae. aegypti mosquitoes in response to DENV or ZIKV. Blockade of the phagocytic function of hemocytes using latex beads induced increased accumulation of hemocytes in the midgut and a reduction in virus infection levels in this organ. In contrast, inhibition of phagocytosis by hemocytes led to increased systemic dissemination and replication of DENV and ZIKV. Hence, our work reveals a dual role for hemocytes in Ae. aegypti mosquitoes, whereby phagocytosis is not required to control viral infection in the midgut but is essential to restrict systemic dissemination. Further understanding of the mechanism behind this duality could help the design of vector-based strategies to prevent transmission of arboviruses.
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Affiliation(s)
- Thiago H J F Leite
- Department of Biochemistry and Immunology, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Álvaro G A Ferreira
- Department of Biochemistry and Immunology, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.,Mosquitos Vetores: Endossimbiontes e Interação Patógeno-Vetor, Instituto René Rachou - Fiocruz, Belo Horizonte, Brazil
| | - Jean-Luc Imler
- Université de Strasbourg, CNRS UPR9022, Inserm U1257, Strasbourg, France
| | - João T Marques
- Department of Biochemistry and Immunology, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.,Université de Strasbourg, CNRS UPR9022, Inserm U1257, Strasbourg, France
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39
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Vommaro ML, Kurtz J, Giglio A. Morphological Characterisation of Haemocytes in the Mealworm Beetle Tenebrio molitor (Coleoptera, Tenebrionidae). INSECTS 2021; 12:insects12050423. [PMID: 34066849 PMCID: PMC8151185 DOI: 10.3390/insects12050423] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/04/2021] [Accepted: 05/06/2021] [Indexed: 11/16/2022]
Abstract
The immunocompetence of the mealworm beetle Tenebrio molitor has been well investigated at molecular and physiological levels, but information on morphological and functional characteristics of its immune cells (haemocytes) is still scarce and fragmentary. This study provides an updated overview of the morphology of circulating immune cells from mealworm beetle adults, using light and transmission electron microscopy. Based on their affinities for May-Grünwald Giemsa stain, haemocytes were defined as either eosinophilic, basophilic or neutral. Ultrastructural descriptions allowed to detect four main cell types in the haemolymph: prohaemocytes, plasmatocytes, granular cells and oenocytoids. The morphological plasticity of haemocytes and the evidence of mitotic circulating cells, intermediate cell stages, as well as autophagic activities suggest haemocyte proliferation, turnover and transdifferentiation as constantly active processes in the haemolymph. Cytochemical tests revealed differences in the distribution of carbohydrates among cell types underling the great plasticity of the immune response and the direct involvement of circulating immune cells in the resource allocation. In addition, our results provide a detailed morphological description of vesicle trafficking, macro- and microautophagy, apoptotic and necrotic processes, confirming the suitability of T. molitor haemocytes as a model for studying evolutionarily conserved cellular mechanisms.
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Affiliation(s)
- Maria Luigia Vommaro
- Department of Biology, Ecology and Earth Science, University of Calabria, 87036 Rende, Italy;
| | - Joachim Kurtz
- Institute for Evolution and Biodiversity, University of Münster, 48149 Münster, Germany;
| | - Anita Giglio
- Department of Biology, Ecology and Earth Science, University of Calabria, 87036 Rende, Italy;
- Correspondence: ; Tel.: +39-098-449-2982; Fax: +39-098-449-2986
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40
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Bitencourt RDOB, Salcedo-Porras N, Umaña-Diaz C, da Costa Angelo I, Lowenberger C. Antifungal immune responses in mosquitoes (Diptera: Culicidae): A review. J Invertebr Pathol 2020; 178:107505. [PMID: 33238166 DOI: 10.1016/j.jip.2020.107505] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 10/27/2020] [Accepted: 11/17/2020] [Indexed: 02/08/2023]
Abstract
Mosquitoes transmit many parasites and pathogens to humans that cause significant morbidity and mortality. As such, we are constantly looking for new methods to reduce mosquito populations, including the use of effective biological controls. Entomopathogenic fungi are excellent candidate biocontrol agents to control mosquitoes. Understanding the complex ecological, environmental, and molecular interactions between hosts and pathogens are essential to create novel, effective and safe biocontrol agents. Understanding how mosquitoes recognize and eliminate pathogens such as entomopathogenic fungi may allow us to create insect-order specific biocontrol agents to reduce pest populations. Here we summarize the current knowledge of fungal infection, colonization, development, and replication within mosquitoes and the innate immune responses of the mosquitoes towards the fungal pathogens, emphasizing those features required for an effective mosquito biocontrol agent.
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Affiliation(s)
- Ricardo de Oliveira Barbosa Bitencourt
- Program in Veterinary Science, Institute of Veterinary Science, Rural Federal University of Rio de Janeiro, Seropédica, RJ, Brazil; Centre for Cell Biology, Development and Disease, Department of Biological Sciences, Simon Fraser University, Burnaby BC V5A 1S6, British Columbia, Canada.
| | - Nicolas Salcedo-Porras
- Centre for Cell Biology, Development and Disease, Department of Biological Sciences, Simon Fraser University, Burnaby BC V5A 1S6, British Columbia, Canada
| | - Claudia Umaña-Diaz
- Centre for Cell Biology, Development and Disease, Department of Biological Sciences, Simon Fraser University, Burnaby BC V5A 1S6, British Columbia, Canada
| | - Isabele da Costa Angelo
- Department of Epidemiology and Public Health, Veterinary Institute, Rural Federal University of Rio de Janeiro, Seropédica, RJ, Brazil
| | - Carl Lowenberger
- Centre for Cell Biology, Development and Disease, Department of Biological Sciences, Simon Fraser University, Burnaby BC V5A 1S6, British Columbia, Canada.
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41
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Yan Y, Hillyer JF. The immune and circulatory systems are functionally integrated across insect evolution. SCIENCE ADVANCES 2020; 6:6/48/eabb3164. [PMID: 33239286 PMCID: PMC7688319 DOI: 10.1126/sciadv.abb3164] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 10/09/2020] [Indexed: 05/11/2023]
Abstract
The immune and circulatory systems of mammals are functionally integrated, as exemplified by the immune function of the spleen and lymph nodes. Similar functional integration exists in the malaria mosquito, Anopheles gambiae, as exemplified by the infection-induced aggregation of hemocytes around the heart valves. Whether this is specific to mosquitoes or a general characteristic of insects remained unknown. We analyzed 68 species from 51 families representing 16 orders and found that infection induces the aggregation of hemocytes and pathogens on the heart of insects from all major branches of the class Insecta. An expanded analysis in the holometabolous mosquito, Aedes aegypti, and the hemimetabolous bed bug, Cimex lectularius, showed that infection induces the aggregation of phagocytic hemocytes on the hearts of distantly related insects, with aggregations mirroring the patterns of hemolymph flow. Therefore, the functional integration of the immune and circulatory systems is conserved across the insect tree of life.
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Affiliation(s)
- Yan Yan
- Department of Biological Sciences, Vanderbilt University, VU Station B 35-1634, Nashville, TN 37235, USA
| | - Julián F Hillyer
- Department of Biological Sciences, Vanderbilt University, VU Station B 35-1634, Nashville, TN 37235, USA.
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42
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Duffield KR, Hampton KJ, Houslay TM, Rapkin J, Hunt J, Sadd BM, Sakaluk SK. Macronutrient intake and simulated infection threat independently affect life history traits of male decorated crickets. Ecol Evol 2020; 10:11766-11778. [PMID: 33144999 PMCID: PMC7593159 DOI: 10.1002/ece3.6813] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 08/07/2020] [Accepted: 08/28/2020] [Indexed: 01/11/2023] Open
Abstract
Nutritional geometry has advanced our understanding of how macronutrients (e.g., proteins and carbohydrates) influence the expression of life history traits and their corresponding trade-offs. For example, recent work has revealed that reproduction and immune function in male decorated crickets are optimized at very different protein:carbohydrate (P:C) dietary ratios. However, it is unclear how an individual's macronutrient intake interacts with its perceived infection status to determine investment in reproduction or other key life history traits. Here, we employed a fully factorial design in which calling effort and immune function were quantified for male crickets fed either diets previously demonstrated to maximize calling effort (P:C = 1:8) or immune function (P:C = 5:1), and then administered a treatment from a spectrum of increasing infection cue intensity using heat-killed bacteria. Both diet and a simulated infection threat independently influenced the survival, immunity, and reproductive effort of males. If they called, males increased calling effort at the low infection cue dose, consistent with the terminal investment hypothesis, but interpretation of responses at the higher threat levels was hampered by the differential mortality of males across infection cue and diet treatments. A high protein, low carbohydrate diet severely reduced the health, survival, and overall fitness of male crickets. There was, however, no evidence of an interaction between diet and infection cue dose on calling effort, suggesting that the threshold for terminal investment was not contingent on diet as investigated here.
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Affiliation(s)
- Kristin R. Duffield
- Behavior, Ecology, Evolution and Systematics SectionSchool of Biological SciencesIllinois State UniversityNormalILUSA
- Present address:
Crop Bioprotection Research UnitUnited States Department of AgricultureNational Center for Agricultural Utilization Research, Agricultural Research ServicePeoriaILUSA
| | - Kylie J. Hampton
- Behavior, Ecology, Evolution and Systematics SectionSchool of Biological SciencesIllinois State UniversityNormalILUSA
- Present address:
Crop Bioprotection Research UnitUnited States Department of AgricultureNational Center for Agricultural Utilization Research, Agricultural Research ServicePeoriaILUSA
| | | | - James Rapkin
- Centre for Ecology and ConservationUniversity of ExeterPenrynUK
| | - John Hunt
- Centre for Ecology and ConservationUniversity of ExeterPenrynUK
- School of Science and Hawkesbury Institute for the EnvironmentWestern Sydney UniversityPenrithNSWAustralia
| | - Ben M. Sadd
- Behavior, Ecology, Evolution and Systematics SectionSchool of Biological SciencesIllinois State UniversityNormalILUSA
| | - Scott K. Sakaluk
- Behavior, Ecology, Evolution and Systematics SectionSchool of Biological SciencesIllinois State UniversityNormalILUSA
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43
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von Bredow YM, von Bredow CR, Trenczek TE. A novel site of haematopoiesis and appearance and dispersal of distinct haemocyte types in the Manduca sexta embryo (Insecta, Lepidoptera). DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 111:103722. [PMID: 32360227 DOI: 10.1016/j.dci.2020.103722] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 04/25/2020] [Accepted: 04/26/2020] [Indexed: 06/11/2023]
Abstract
With a set of haemocyte specific markers novel findings on haematopoiesis in the Manduca sexta embryo are presented. We identify a hitherto unknown paired haematopoietic cluster, the abdominal haemocyte cluster in abdominal segment 7 (A7-HCC). These clusters are localised at distinct positions and are established at around katatrepsis. Later in embryogenesis, the A7-HCCs disintegrate, thereby releasing numerous embryonic plasmatocytes which disperse both anteriorly and posteriorly. These cells follow stereotypic migration routes projecting anteriorly. The thoracic larval haematopoietic organs are established at around midembryogenesis. We identify embryonic oenocytoids in the M. sexta embryo for the first time. They appear in the head region roughly at the same time as the A7-HCCs occur and successively disperse in the body cavity during development. Localisation of the prophenoloxidase (proPO) mRNA and of the proPO protein are identical. Morphological, cytometric and antigenic traits show three independently generated haemocyte types during embryogenesis.
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Affiliation(s)
- Yvette M von Bredow
- Justus-Liebig-Universität Gießen, Institut für Allgemeine Zoologie und Entwicklungsbiologie, Zelluläre Erkennungs- und Abwehrprozesse, Stephanstraße 24, 35390, Gießen, Germany.
| | - Christoph-Rüdiger von Bredow
- Technische Universität Dresden, Fakultät Biologie, Institut für Zoologie, Professur für Allgemeine Zoologie und Entwicklungsbiologie, Zellescher Web 20 b, 01217, Dresden, Germany
| | - Tina E Trenczek
- Justus-Liebig-Universität Gießen, Institut für Allgemeine Zoologie und Entwicklungsbiologie, Zelluläre Erkennungs- und Abwehrprozesse, Stephanstraße 24, 35390, Gießen, Germany
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44
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Sorrell MR, Killian KA. Innate immune system function following systemic RNA-interference of the Fragile X Mental Retardation 1 gene in the cricket Acheta domesticus. JOURNAL OF INSECT PHYSIOLOGY 2020; 126:104097. [PMID: 32791072 DOI: 10.1016/j.jinsphys.2020.104097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 06/02/2020] [Accepted: 08/06/2020] [Indexed: 06/11/2023]
Abstract
Fragile X syndrome (FXS), caused by a mutation in the Fragile X Mental Retardation 1 (FMR1) gene, is a common form of inherited mental retardation. Mutation of the gene leads to a loss of the gene product Fragile X Mental Retardation Protein (FMRP). While a loss of FMRP has been primarily associated with neural and cognitive deficits, it has also been reported to lead to immune system dysfunction in both humans and flies. We used the Acheta domesticus transcriptome to identify a highly conserved cricket ortholog of FMR1 (adfmr1). We cloned a partial cDNA of adfmr1, used systemic RNA interference (RNAi) to knockdown adfmr1 expression, and examined the impact of this knockdown (KD) on the cellular and humoral responses of the insect innate immune system. Following RNAi, both male and female crickets exhibited an increase in the number of circulating hemocytes, a decrease in total hemolymph phenoloxidase (PO) activity, and an increase in fat body lysozyme expression. Despite similar changes in these immune parameters in both sexes, male and female crickets responded differently to an immune challenge. Most KD males failed to survive an intra-abdominal injection of bacterial lipopolysaccharide, while KD females were just as likely as control females to survive this challenge. Our results support that decreased fmr1 expression can alter the cellular and humoral defenses of the insect innate immune system, and may lead to a decrease in male, but not female, immunocompetence.
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Affiliation(s)
- Mollie R Sorrell
- Department of Biology, Miami University, 258 Pearson Hall, Oxford, OH 45056, USA; Department of Biology, Defiance College, Defiance, OH 43512, USA
| | - Kathleen A Killian
- Department of Biology, Miami University, 258 Pearson Hall, Oxford, OH 45056, USA.
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45
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Samaddar S, Marnin L, Butler LR, Pedra JHF. Immunometabolism in Arthropod Vectors: Redefining Interspecies Relationships. Trends Parasitol 2020; 36:807-815. [PMID: 32819827 PMCID: PMC7897511 DOI: 10.1016/j.pt.2020.07.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 07/13/2020] [Accepted: 07/18/2020] [Indexed: 02/08/2023]
Abstract
Metabolism influences biochemical networks, and arthropod vectors are endowed with an immune system that affects microbial acquisition, persistence, and transmission to humans and other animals. Here, we aim to persuade the scientific community to expand their interests in immunometabolism beyond mammalian hosts and towards arthropod vectors. Immunometabolism investigates the interplay of metabolism and immunology. We provide a conceptual framework for investigators from diverse disciplines and indicate that relationships between microbes, mammalian hosts and their hematophagous arthropods may result in cost-effective (mutualism) or energetically expensive (parasitism) interactions. We argue that disparate resource allocations between species may partially explain why some microbes act as pathogens when infecting humans and behave as mutualistic or commensal organisms when colonizing arthropod vectors.
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Affiliation(s)
- Sourabh Samaddar
- Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Liron Marnin
- Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - L Rainer Butler
- Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Joao H F Pedra
- Department of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, MD, USA.
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46
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Raddi G, Barletta ABF, Efremova M, Ramirez JL, Cantera R, Teichmann SA, Barillas-Mury C, Billker O. Mosquito cellular immunity at single-cell resolution. Science 2020; 369:1128-1132. [PMID: 32855340 DOI: 10.1126/science.abc0322] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 06/30/2020] [Indexed: 11/02/2022]
Abstract
Hemocytes limit the capacity of mosquitoes to transmit human pathogens. Here we profile the transcriptomes of 8506 hemocytes of Anopheles gambiae and Aedes aegypti mosquito vectors. Our data reveal the functional diversity of hemocytes, with different subtypes of granulocytes expressing distinct and evolutionarily conserved subsets of effector genes. A previously unidentified cell type in An. gambiae, which we term "megacyte," is defined by a specific transmembrane protein marker (TM7318) and high expression of lipopolysaccharide-induced tumor necrosis factor-α transcription factor 3 (LL3). Knockdown experiments indicate that LL3 mediates hemocyte differentiation during immune priming. We identify and validate two main hemocyte lineages and find evidence of proliferating granulocyte populations. This atlas of medically relevant invertebrate immune cells at single-cell resolution identifies cellular events that underpin mosquito immunity to malaria infection.
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Affiliation(s)
- Gianmarco Raddi
- Wellcome Sanger Institute, Hinxton, Cambridge CB10 2AZ, UK.,Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | - Ana Beatriz F Barletta
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | | | - Jose Luis Ramirez
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | - Rafael Cantera
- Zoology Department, Stockholm University, Stockholm S-10691, Sweden.,Departamento de Biología del Neurodesarrollo, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo 11600, Uruguay
| | - Sarah A Teichmann
- Wellcome Sanger Institute, Hinxton, Cambridge CB10 2AZ, UK.,Institute and Department of Physics, University of Cambridge, Cambridge CB3 0HE, UK
| | - Carolina Barillas-Mury
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA.
| | - Oliver Billker
- Wellcome Sanger Institute, Hinxton, Cambridge CB10 2AZ, UK. .,Molecular Infection Medicine Sweden, Molecular Biology Department, Umeå University, Umeå S-90187, Sweden
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47
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Wei D, Hou J, Zheng K, Jin X, Xie Q, Cheng L, Sun X. Suicide Gene Therapy Against Malignant Gliomas by the Local Delivery of Genetically Engineered Umbilical Cord Mesenchymal Stem Cells as Cellular Vehicles. Curr Gene Ther 2020; 19:330-341. [PMID: 31657679 DOI: 10.2174/1566523219666191028103703] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Revised: 10/13/2019] [Accepted: 10/18/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND Glioblastoma (GBM) is a malignant tumor that is difficult to eliminate, and new therapies are thus strongly desired. Mesenchymal stem cells (MSCs) have the ability to locate to injured tissues, inflammation sites and tumors and are thus good candidates for carrying antitumor genes for the treatment of tumors. Treating GBM with MSCs that have been transduced with the herpes simplex virus thymidine kinase (HSV-TK) gene has brought significant advances because MSCs can exert a bystander effect on tumor cells upon treatment with the prodrug ganciclovir (GCV). OBJECTIVE In this study, we aimed to determine whether HSV-TK-expressing umbilical cord mesenchymal stem cells (MSCTKs) together with prodrug GCV treatment could exert a bystander killing effect on GBM. METHODS AND RESULTS Compared with MSCTK: U87 ratio at 1:10,1:100 and 1:100, GCV concentration at 2.5µM or 250µM, when MSCTKs were cocultured with U87 cells at a ratio of 1:1, 25 µM GCV exerted a more stable killing effect. Higher amounts of MSCTKs cocultured with U87 cells were correlated with a better bystander effect exerted by the MSCTK/GCV system. We built U87-driven subcutaneous tumor models and brain intracranial tumor models to evaluate the efficiency of the MSCTK/GCV system on subcutaneous and intracranial tumors and found that MSCTK/GCV was effective in both models. The ratio of MSCTKs and tumor cells played a critical role in this therapeutic effect, with a higher MSCTK/U87 ratio exerting a better effect. CONCLUSION This research suggested that the MSCTK/GCV system exerts a strong bystander effect on GBM tumor cells, and this system may be a promising assistant method for GBM postoperative therapy.
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Affiliation(s)
- Dan Wei
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Sciences, Central South University, Changsha, Hunan, China.,National Engineering and Research Center of Human Stem Cell, Changsha, Hunan, China
| | - JiaLi Hou
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Sciences, Central South University, Changsha, Hunan, China.,National Engineering and Research Center of Human Stem Cell, Changsha, Hunan, China
| | - Ke Zheng
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Sciences, Central South University, Changsha, Hunan, China.,National Engineering and Research Center of Human Stem Cell, Changsha, Hunan, China
| | - Xin Jin
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Sciences, Central South University, Changsha, Hunan, China.,National Engineering and Research Center of Human Stem Cell, Changsha, Hunan, China
| | - Qi Xie
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Sciences, Central South University, Changsha, Hunan, China.,National Engineering and Research Center of Human Stem Cell, Changsha, Hunan, China
| | - Lamei Cheng
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Sciences, Central South University, Changsha, Hunan, China.,National Engineering and Research Center of Human Stem Cell, Changsha, Hunan, China
| | - Xuan Sun
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Sciences, Central South University, Changsha, Hunan, China.,National Engineering and Research Center of Human Stem Cell, Changsha, Hunan, China
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48
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Estévez-Lao TY, Sigle LT, Gomez SN, Hillyer JF. Nitric oxide produced by periostial hemocytes modulates the bacterial infection-induced reduction of the mosquito heart rate. J Exp Biol 2020; 223:jeb225821. [PMID: 32561636 DOI: 10.1242/jeb.225821] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 06/16/2020] [Indexed: 12/21/2022]
Abstract
The circulatory and immune systems of mosquitoes are functionally integrated. An infection induces the migration of hemocytes to the dorsal vessel, and specifically, to the regions surrounding the ostia of the heart. These periostial hemocytes phagocytose pathogens in the areas of the hemocoel that experience the highest hemolymph flow. Here, we investigated whether a bacterial infection affects cardiac rhythmicity in the African malaria mosquito, Anopheles gambiae We discovered that infection with Escherichia coli, Staphylococcus aureus and Staphylococcus epidermidis, but not Micrococcus luteus, reduces the mosquito heart rate and alters the proportional directionality of heart contractions. Infection does not alter the expression of genes encoding crustacean cardioactive peptide (CCAP), FMRFamide, corazonin, neuropeptide F or short neuropeptide F, indicating that they do not drive the cardiac phenotype. Infection upregulates the transcription of two superoxide dismutase (SOD) genes, catalase and a glutathione peroxidase, but dramatically induces upregulation of nitric oxide synthase (NOS) in both the heart and hemocytes. Within the heart, nitric oxide synthase is produced by periostial hemocytes, and chemically inhibiting the production of nitric oxide using l-NAME reverses the infection-induced cardiac phenotype. Finally, infection induces the upregulation of two lysozyme genes in the heart and other tissues, and treating mosquitoes with lysozyme reduces the heart rate in a manner reminiscent of the infection phenotype. These data demonstrate an exciting new facet of the integration between the immune and circulatory systems of insects, whereby a hemocyte-produced factor with immune activity, namely nitric oxide, modulates heart physiology.
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Affiliation(s)
- Tania Y Estévez-Lao
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
| | - Leah T Sigle
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
| | - Scherly N Gomez
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
| | - Julián F Hillyer
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
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49
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Potts R, King JG, Pietri JE. Ex vivo characterization of the circulating hemocytes of bed bugs and their responses to bacterial exposure. J Invertebr Pathol 2020; 174:107422. [PMID: 32526226 PMCID: PMC9254597 DOI: 10.1016/j.jip.2020.107422] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 06/03/2020] [Accepted: 06/04/2020] [Indexed: 11/17/2022]
Abstract
Bed bugs (Cimex spp.) are urban pests of global importance. Knowledge of the immune system of bed bugs has implications for understanding their susceptibility to biological control agents, their potential to transmit human pathogens, and the basic comparative immunology of insects. Nonetheless, the immunological repertoire of the family Cimicidae remains poorly characterized. Here, we use microscopy, flow cytometry, and RNA sequencing to provide a basal characterization of the circulating hemocytes of the common bed bug, Cimex lectularius. We also examine the responses of these specialized cells to E. coli exposure using the same techniques. Our results show that circulating hemocytes are comprised of at least four morphologically distinct cell types that are capable of phagocytosis, undergo degranulation, and exhibit additional markers of activation following stimulation, including size shift and DNA replication. Furthermore, transcriptomic profiling reveals expression of predicted Toll/IMD signaling pathway components, antimicrobial effectors and other potentially immunoresponsive genes in these cells. Together, our data demonstrate the conservation of several canonical cellular immune responses in the common bed bug and provide a foundation for additional mechanistic immunological studies with specific pathogens of interest.
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Affiliation(s)
- Rashaun Potts
- University of South Dakota, Sanford School of Medicine, Division of Basic Biomedical Sciences, Vermillion, SD, United States
| | - Jonas G King
- Mississippi State University, Department of Biochemistry, Molecular Biology, Entomology & Plant Pathology, Starkville, MS, United States
| | - Jose E Pietri
- University of South Dakota, Sanford School of Medicine, Division of Basic Biomedical Sciences, Vermillion, SD, United States.
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Powers JC, Turangan R, Joosse BA, Hillyer JF. Adult Mosquitoes Infected with Bacteria Early in Life Have Stronger Antimicrobial Responses and More Hemocytes after Reinfection Later in Life. INSECTS 2020; 11:insects11060331. [PMID: 32481519 PMCID: PMC7349202 DOI: 10.3390/insects11060331] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 05/25/2020] [Accepted: 05/27/2020] [Indexed: 12/20/2022]
Abstract
The immunological strategies employed by insects to overcome infection vary with the type of infection and may change with experience. We investigated how a bacterial infection in the hemocoel of the African malaria mosquito, Anopheles gambiae, prepares the immune system to face a subsequent bacterial infection. For this, adult female mosquitoes were separated into three groups—unmanipulated, injured, or infected with Escherichia coli—and five days later all the mosquitoes were infected with a different strain of E. coli. We found that an injury or a bacterial infection early in life enhances the ability of mosquitoes to kill bacteria later in life. This protection results in higher mosquito survival and is associated with an increased hemocyte density, altered phagocytic activity by individual hemocytes, and the increased expression of nitric oxide synthase and perhaps prophenoloxidase 6. Protection from a second infection likely occurs because of heightened immune awareness due to an already existing infection instead of memory arising from an earlier, cured infection. This study highlights the dynamic nature of the mosquito immune response and how one infection prepares mosquitoes to survive a subsequent infection.
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