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Ewald S, Nasuhidehnavi A, Feng TY, Lesani M, McCall LI. The intersection of host in vivo metabolism and immune responses to infection with kinetoplastid and apicomplexan parasites. Microbiol Mol Biol Rev 2024; 88:e0016422. [PMID: 38299836 PMCID: PMC10966954 DOI: 10.1128/mmbr.00164-22] [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] [Indexed: 02/02/2024] Open
Abstract
SUMMARYProtozoan parasite infection dramatically alters host metabolism, driven by immunological demand and parasite manipulation strategies. Immunometabolic checkpoints are often exploited by kinetoplastid and protozoan parasites to establish chronic infection, which can significantly impair host metabolic homeostasis. The recent growth of tools to analyze metabolism is expanding our understanding of these questions. Here, we review and contrast host metabolic alterations that occur in vivo during infection with Leishmania, trypanosomes, Toxoplasma, Plasmodium, and Cryptosporidium. Although genetically divergent, there are commonalities among these pathogens in terms of metabolic needs, induction of the type I immune responses required for clearance, and the potential for sustained host metabolic dysbiosis. Comparing these pathogens provides an opportunity to explore how transmission strategy, nutritional demand, and host cell and tissue tropism drive similarities and unique aspects in host response and infection outcome and to design new strategies to treat disease.
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Affiliation(s)
- Sarah Ewald
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Azadeh Nasuhidehnavi
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma, USA
| | - Tzu-Yu Feng
- Department of Microbiology, Immunology, and Cancer Biology at the Carter Immunology Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Mahbobeh Lesani
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
| | - Laura-Isobel McCall
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma, USA
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
- Laboratories of Molecular Anthropology and Microbiome Research, University of Oklahoma, Norman, Oklahoma, USA
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, California, USA
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2
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González-Acosta S, Baca-González V, Asensio-Calavia P, Otazo-Pérez A, López MR, Morales-delaNuez A, Pérez de la Lastra JM. Efficient Oral Priming of Tenebrio molitor Larvae Using Heat-Inactivated Microorganisms. Vaccines (Basel) 2022; 10:vaccines10081296. [PMID: 36016184 PMCID: PMC9415734 DOI: 10.3390/vaccines10081296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/04/2022] [Accepted: 08/06/2022] [Indexed: 11/16/2022] Open
Abstract
Microbial resistance is a global health problem that will increase over time. Advances in insect antimicrobial peptides (AMPs) offer a powerful new approach to combat antimicrobial resistance. Invertebrates represent a rich group of animals for the discovery of new antimicrobial agents due to their high diversity and the presence of adaptive immunity or “immune priming”. Here, we report a priming approach for Tenebrio molitor that simulates natural infection via the oral route. This oral administration has the advantage of minimizing the stress caused by conventional priming techniques and could be a viable method for mealworm immunity studies. When using inactivated microorganisms for oral priming, our results showed an increased survival of T. molitor larvae after exposure to various pathogens. This finding was consistent with the induction of antimicrobial activity in the hemolymph of primed larvae. Interestingly, the hemolymph of larvae orally primed with Escherichia coli showed constitutive activity against Staphylococcus aureus and heterologous activity for other Gram-negative bacteria, such as Salmonella enterica. The priming of T. molitor is generally performed via injection of the microorganism. To our knowledge, this is the first report describing the oral administration of heat-inactivated microorganisms for priming mealworms. This technique has the advantage of reducing the stress that occurs with the conventional methods for priming vertebrates.
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Affiliation(s)
- Sergio González-Acosta
- Biotechnology of Macromolecules Research Group, Instituto de Productos Naturales y Agrobiología, (IPNA-CSIC), 38206 San Cristóbal de la Laguna, Spain
- Escuela de Doctorado y Estudios de Posgrado, Universidad de La Laguna Avda, Astrofísico Francisco Sánchez, SN. Edificio Calabaza-Apdo, 456, 38200 San Cristóbal de La Laguna, Spain
| | - Victoria Baca-González
- Biotechnology of Macromolecules Research Group, Instituto de Productos Naturales y Agrobiología, (IPNA-CSIC), 38206 San Cristóbal de la Laguna, Spain
| | - Patricia Asensio-Calavia
- Biotechnology of Macromolecules Research Group, Instituto de Productos Naturales y Agrobiología, (IPNA-CSIC), 38206 San Cristóbal de la Laguna, Spain
- Escuela de Doctorado y Estudios de Posgrado, Universidad de La Laguna Avda, Astrofísico Francisco Sánchez, SN. Edificio Calabaza-Apdo, 456, 38200 San Cristóbal de La Laguna, Spain
| | - Andrea Otazo-Pérez
- Biotechnology of Macromolecules Research Group, Instituto de Productos Naturales y Agrobiología, (IPNA-CSIC), 38206 San Cristóbal de la Laguna, Spain
- Escuela de Doctorado y Estudios de Posgrado, Universidad de La Laguna Avda, Astrofísico Francisco Sánchez, SN. Edificio Calabaza-Apdo, 456, 38200 San Cristóbal de La Laguna, Spain
| | - Manuel R. López
- Biotechnology of Macromolecules Research Group, Instituto de Productos Naturales y Agrobiología, (IPNA-CSIC), 38206 San Cristóbal de la Laguna, Spain
| | - Antonio Morales-delaNuez
- Biotechnology of Macromolecules Research Group, Instituto de Productos Naturales y Agrobiología, (IPNA-CSIC), 38206 San Cristóbal de la Laguna, Spain
| | - José Manuel Pérez de la Lastra
- Biotechnology of Macromolecules Research Group, Instituto de Productos Naturales y Agrobiología, (IPNA-CSIC), 38206 San Cristóbal de la Laguna, Spain
- Correspondence: ; Tel.: +34-922-474334
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3
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Ji J, Shen D, Zhang S, Wang L, An C. Serpin-4 Facilitates Baculovirus Infection by Inhibiting Melanization in Asian Corn Borer, Ostrinia furnacalis (Guenée). Front Immunol 2022; 13:905357. [PMID: 35757693 PMCID: PMC9218052 DOI: 10.3389/fimmu.2022.905357] [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] [Received: 03/27/2022] [Accepted: 04/25/2022] [Indexed: 11/13/2022] Open
Abstract
Phenoloxidase (PO)-catalyzed melanization is a vital immune response in insects for defense against pathogen infection. This process is mediated by clip domain serine proteases and regulated by members of the serpin superfamily. We here revealed that the infection of Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) significantly inhibited the PO activity in Ostrinia furnacalis hemolymph and induced the expression of O. furnacalis serpin-4. Addition of recombinant serpin-4 protein to O. furnacalis hemolymph resulted in a great increase of AcMNPV copies. Serpin-4 significantly suppressed the PO activity and the amidase activity in cleaving colorimetric substrate IEARpNA (IEARase activity) of hemolymph. Further experiments indicated it formed covalent complexes with three serine proteases (SP1, SP13 and SP105) and prevented them from cleaving their cognate downstream proteases in vitro. Altogether, O. furnacalis melanization restricted AcMNPV replication and serpin-4 facilitated AcMNPV infection by inhibiting serine proteases, SP1, SP13, and SP105 which were all involved in the melanization response.
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Affiliation(s)
- Jiayue Ji
- Department of Entomology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Dongxu Shen
- Department of Entomology, College of Plant Protection, China Agricultural University, Beijing, China.,Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, China.,Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture and Rural Affairs, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, China
| | - Shasha Zhang
- Department of Entomology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Lei Wang
- Department of Entomology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Chunju An
- Department of Entomology, College of Plant Protection, China Agricultural University, Beijing, China
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4
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Hendrickx S, Caljon G. The effect of the sugar metabolism on Leishmania infantum promastigotes inside the gut of Lutzomyia longipalpis: A sweet relationship? PLoS Negl Trop Dis 2022; 16:e0010293. [PMID: 35385472 PMCID: PMC8985994 DOI: 10.1371/journal.pntd.0010293] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Accepted: 03/02/2022] [Indexed: 11/26/2022] Open
Abstract
It is well-known that Leishmania parasites can alter the behavior of the sand fly vector in order to increase their transmission potential. However, little is known about the contribution of the infecting host’s blood composition on subsequent sand fly infection and survival. This study focused on the host’s glucose metabolism and the insulin/insulin-like growth factor 1 (IGF-1) pathway as both metabolic processes are known to impact vector-parasite interactions of other protozoa and insect species. The focus of this study was inspired by the observation that the glycemic levels in the blood of infected Syrian golden hamsters inversely correlated to splenic and hepatic parasite burdens. To evaluate the biological impact of these findings on further transmission, Lutzomyia longipalpis sand flies were infected with blood that was artificially supplemented with different physiological concentrations of several monosaccharides, insulin or IGF-1. Normoglycemic levels resulted in transiently higher parasite loads and faster appearance of metacyclics, whereas higher carbohydrate and insulin/IGF-1 levels favored sand fly survival. Although the recorded effects were modest or transient of nature, these observations support the concept that the host blood biochemistry may affect Leishmania transmission and sand fly longevity. Past research on the interaction between the Leishmania parasite and the sand fly vector has revealed that Leishmania is capable of changing vector behavior to favor transmission of parasites in the environment. Little is known about the impact of host blood composition on parasite development inside the vector and on vector survival. Here, we showed that parasite burdens in the spleen and the liver inversely correlated to the serum blood glucose levels of infected animals, which triggered us to further investigate the effect of blood monosaccharides, insulin and insulin-like growth factor 1 (IGF-1) on sand fly infection and survival. We demonstrated that normal serum glucose levels in the initial parasitized blood meal resulted in transiently higher parasite loads and a faster appearance of infectious parasites, whereas higher sugar and insulin/IGF-1 levels favored sand fly survival, which supports the concept that the host blood biochemistry may affect Leishmania transmission and sand fly longevity.
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Affiliation(s)
- Sarah Hendrickx
- Laboratory of Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Antwerp, Belgium
- * E-mail: (SH); (GC)
| | - Guy Caljon
- Laboratory of Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Antwerp, Belgium
- * E-mail: (SH); (GC)
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5
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Leprêtre M, Almunia C, Armengaud J, Le Guernic A, Salvador A, Geffard A, Palos-Ladeiro M. Identification of immune-related proteins of Dreissena polymorpha hemocytes and plasma involved in host-microbe interactions by differential proteomics. Sci Rep 2020; 10:6226. [PMID: 32277127 PMCID: PMC7148315 DOI: 10.1038/s41598-020-63321-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 03/27/2020] [Indexed: 12/04/2022] Open
Abstract
Biological responses of zebra mussel Dreissena polymorpha are investigated to assess the impact of contaminants on aquatic organisms and ecosystems. In addition to concentrate chemical contaminants in their tissues, zebra mussels accumulate several microorganisms such as viruses, protozoa and bacteria. In order to understand the molecular mechanisms involved in the defence against microorganisms this study aims at identifying immune proteins from D. polymorpha hemolymph involved in defence against protozoa and viruses. For this purpose, hemolymph were exposed ex vivo to Cryptosporidium parvum and RNA poly I:C. Differential proteomics on both hemocytes and plasma revealed immune proteins modulated under exposures. Different patterns of response were observed after C. parvum and RNA poly I:C exposures. The number of modulated proteins per hemolymphatic compartments suggest that C. parvum is managed in cells while RNA poly I:C is managed in plasma after 4 h exposure. BLAST annotation and GO terms enrichment analysis revealed further characteristics of immune mechanisms. Results showed that many proteins involved in the recognition and destruction of microorganisms were modulated in both exposure conditions, while proteins related to phagocytosis and apoptosis were exclusively modulated by C. parvum. This differential proteomic analysis highlights in zebra mussels modulated proteins involved in the response to microorganisms, which reflect a broad range of immune mechanisms such as recognition, internalization and destruction of microorganisms. This study paves the way for the identification of new markers of immune processes that can be used to assess the impact of both chemical and biological contaminations on the health status of aquatic organisms.
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Affiliation(s)
- Maxime Leprêtre
- Université de Reims Champagne-Ardenne, UMR-I 02 INERIS-URCA-ULH SEBIO Stress Environnementaux et BIOsurveillance des milieux aquatiques, UFR Sciences Exactes et Naturelles, Campus du Moulin de la Housse, BP 1039, 51687, Reims, CEDEX, France
- Université de Lyon, Université Claude Bernard Lyon 1, Institut des Sciences Analytiques, CNRS UMR 5280, F-69100, Villeurbanne, France
| | - Christine Almunia
- Laboratoire Innovations Technologiques pour la Détection et le Diagnostic (Li2D), Service de Pharmacologie et Immunoanalyse (SPI), CEA, INRA, F-30207, Bagnols-sur-Cèze, France
| | - Jean Armengaud
- Laboratoire Innovations Technologiques pour la Détection et le Diagnostic (Li2D), Service de Pharmacologie et Immunoanalyse (SPI), CEA, INRA, F-30207, Bagnols-sur-Cèze, France
| | - Antoine Le Guernic
- Université de Reims Champagne-Ardenne, UMR-I 02 INERIS-URCA-ULH SEBIO Stress Environnementaux et BIOsurveillance des milieux aquatiques, UFR Sciences Exactes et Naturelles, Campus du Moulin de la Housse, BP 1039, 51687, Reims, CEDEX, France
| | - Arnaud Salvador
- Université de Lyon, Université Claude Bernard Lyon 1, Institut des Sciences Analytiques, CNRS UMR 5280, F-69100, Villeurbanne, France
| | - Alain Geffard
- Université de Reims Champagne-Ardenne, UMR-I 02 INERIS-URCA-ULH SEBIO Stress Environnementaux et BIOsurveillance des milieux aquatiques, UFR Sciences Exactes et Naturelles, Campus du Moulin de la Housse, BP 1039, 51687, Reims, CEDEX, France
| | - Mélissa Palos-Ladeiro
- Université de Reims Champagne-Ardenne, UMR-I 02 INERIS-URCA-ULH SEBIO Stress Environnementaux et BIOsurveillance des milieux aquatiques, UFR Sciences Exactes et Naturelles, Campus du Moulin de la Housse, BP 1039, 51687, Reims, CEDEX, France.
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6
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Yan Y, Hillyer JF. Complement-like proteins TEP1, TEP3 and TEP4 are positive regulators of periostial hemocyte aggregation in the mosquito Anopheles gambiae. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2019; 107:1-9. [PMID: 30690067 DOI: 10.1016/j.ibmb.2019.01.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 01/16/2019] [Accepted: 01/18/2019] [Indexed: 06/09/2023]
Abstract
The mosquito immune and circulatory systems are functionally integrated. During an infection, hemocytes aggregate around the ostia (valves) of the dorsal vessel - areas of the heart called the periostial regions - where they phagocytose live and melanized pathogens. Although periostial hemocyte aggregation is an immune response that occurs following infection with bacteria and malaria parasites, the molecular basis of this process remains poorly understood. Here, we show that the thioester-containing proteins, TEP1, TEP3 and TEP4 are positive regulators of periostial hemocyte aggregation in the African malaria mosquito, Anopheles gambiae. RNAi-based knockdown of TEP1, TEP3 and TEP4 resulted in fewer periostial hemocytes following Escherichia coli infection, without affecting the adjacent population of non-periostial, sessile hemocytes. Moreover, knockdown of TEP1, TEP3 and TEP4 expression resulted in reduced bacterial accumulation and melanin deposition at the periostial regions. Finally, this study confirmed the role that TEP1 plays in reducing infection intensity in the hemocoel. Overall, this research shows that the complement-like proteins, TEP1, TEP3 and TEP4, are positive regulators of the functional integration between the immune and circulatory systems of mosquitoes.
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Affiliation(s)
- Yan Yan
- 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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7
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Sigle LT, Hillyer JF. Mosquito Hemocytes Associate With Circulatory Structures That Support Intracardiac Retrograde Hemolymph Flow. Front Physiol 2018; 9:1187. [PMID: 30210361 PMCID: PMC6121077 DOI: 10.3389/fphys.2018.01187] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 08/07/2018] [Indexed: 01/28/2023] Open
Abstract
A powerful immune system protects mosquitoes from pathogens and influences their ability to transmit disease. The mosquito's immune and circulatory systems are functionally integrated, whereby intense immune processes occur in areas of high hemolymph flow. The primary circulatory organ of mosquitoes is the dorsal vessel, which consists of a thoracic aorta and an abdominal heart. In adults of the African malaria mosquito, Anopheles gambiae, the heart periodically alternates contraction direction, resulting in intracardiac hemolymph flowing toward the head (anterograde) and toward the posterior of the abdomen (retrograde). During anterograde contractions, hemolymph enters the dorsal vessel through ostia located in abdominal segments 2-7, and exits through an excurrent opening located in the head. During retrograde contractions, hemolymph enters the dorsal vessel through ostia located at the thoraco-abdominal junction, and exits through posterior excurrent openings located in the eighth abdominal segment. The ostia in abdominal segments 2 to 7-which function in anterograde intracardiac flow-are sites of intense immune activity, as a subset of hemocytes, called periostial hemocytes, respond to infection by aggregating, phagocytosing, and killing pathogens. Here, we assessed whether hemocytes are present and active at two sites important for retrograde intracardiac hemolymph flow: the thoraco-abdominal ostia and the posterior excurrent openings of the heart. We detected sessile hemocytes around both of these structures, and these hemocytes readily engage in phagocytosis. However, they are few in number and a bacterial infection does not induce the aggregation of additional hemocytes at these locations. Finally, we describe the process of hemocyte attachment and detachment to regions of the dorsal vessel involved in intracardiac retrograde flow.
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Affiliation(s)
| | - Julián F. Hillyer
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, United States
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8
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Lefevre T, Ohm J, Dabiré KR, Cohuet A, Choisy M, Thomas MB, Cator L. Transmission traits of malaria parasites within the mosquito: Genetic variation, phenotypic plasticity, and consequences for control. Evol Appl 2017; 11:456-469. [PMID: 29636799 PMCID: PMC5891056 DOI: 10.1111/eva.12571] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 10/23/2017] [Indexed: 12/16/2022] Open
Abstract
Evaluating the risk of emergence and transmission of vector‐borne diseases requires knowledge of the genetic and environmental contributions to pathogen transmission traits. Compared to the significant effort devoted to understanding the biology of malaria transmission from vertebrate hosts to mosquito vectors, the strategies that malaria parasites have evolved to maximize transmission from vectors to vertebrate hosts have been largely overlooked. While determinants of infection success within the mosquito host have recently received attention, the causes of variability for other key transmission traits of malaria, namely the duration of parasite development and its virulence within the vector, as well as its ability to alter mosquito behavior, remain largely unknown. This important gap in our knowledge needs to be bridged in order to obtain an integrative view of the ecology and evolution of malaria transmission strategies. Associations between transmission traits also need to be characterized, as they trade‐offs and constraints could have important implications for understanding the evolution of parasite transmission. Finally, theoretical studies are required to evaluate how genetic and environmental influences on parasite transmission traits can shape malaria dynamics and evolution in response to disease control.
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Affiliation(s)
- Thierry Lefevre
- MIVEGEC, IRD, CNRS University of Montpellier Montpellier France.,Institut de Recherche en Sciences de la Santé (IRSS) Bobo Dioulasso Burkina Faso.,Laboratoire Mixte International sur les Vecteurs (LAMIVECT) Bobo Dioulasso Burkina Faso
| | - Johanna Ohm
- Department of Entomology and Center for Infectious Disease Dynamics Penn State University University Park PA USA
| | - Kounbobr R Dabiré
- Institut de Recherche en Sciences de la Santé (IRSS) Bobo Dioulasso Burkina Faso.,Laboratoire Mixte International sur les Vecteurs (LAMIVECT) Bobo Dioulasso Burkina Faso
| | - Anna Cohuet
- MIVEGEC, IRD, CNRS University of Montpellier Montpellier France
| | - Marc Choisy
- MIVEGEC, IRD, CNRS University of Montpellier Montpellier France.,Oxford University Clinical Research Unit Hanoi Vietnam
| | - Matthew B Thomas
- Department of Entomology and Center for Infectious Disease Dynamics Penn State University University Park PA USA
| | - Lauren Cator
- Grand Challenges in Ecosystems and Environment Imperial College London Ascot UK
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League GP, Estévez-Lao TY, Yan Y, Garcia-Lopez VA, Hillyer JF. Anopheles gambiae larvae mount stronger immune responses against bacterial infection than adults: evidence of adaptive decoupling in mosquitoes. Parasit Vectors 2017; 10:367. [PMID: 28764812 PMCID: PMC5539753 DOI: 10.1186/s13071-017-2302-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Accepted: 07/20/2017] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND The immune system of adult mosquitoes has received significant attention because of the ability of females to vector disease-causing pathogens while ingesting blood meals. However, few studies have focused on the immune system of larvae, which, we hypothesize, is highly robust due to the high density and diversity of microorganisms that larvae encounter in their aquatic environments and the strong selection pressures at work in the larval stage to ensure survival to reproductive maturity. Here, we surveyed a broad range of cellular and humoral immune parameters in larvae of the malaria mosquito, Anopheles gambiae, and compared their potency to that of newly-emerged adults and older adults. RESULTS We found that larvae kill bacteria in their hemocoel with equal or greater efficiency compared to newly-emerged adults, and that antibacterial ability declines further with adult age, indicative of senescence. This phenotype correlates with more circulating hemocytes and a differing spatial arrangement of sessile hemocytes in larvae relative to adults, as well as with the individual hemocytes of adults carrying a greater phagocytic burden. The hemolymph of larvae also possesses markedly stronger antibacterial lytic and melanization activity than the hemolymph of adults. Finally, infection induces a stronger transcriptional upregulation of immunity genes in larvae than in adults, including differences in the immunity genes that are regulated. CONCLUSIONS These results demonstrate that immunity is strongest in larvae and declines after metamorphosis and with adult age, and suggest that adaptive decoupling, or the independent evolution of larval and adult traits made possible by metamorphosis, has occurred in the mosquito lineage.
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Affiliation(s)
- Garrett P. League
- Department of Biological Sciences, Vanderbilt University, Nashville, TN USA
| | | | - Yan Yan
- 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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10
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Sigle LT, Hillyer JF. Mosquito hemocytes preferentially aggregate and phagocytose pathogens in the periostial regions of the heart that experience the most hemolymph flow. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2016; 55:90-101. [PMID: 26526332 DOI: 10.1016/j.dci.2015.10.018] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 10/19/2015] [Accepted: 10/20/2015] [Indexed: 06/05/2023]
Abstract
When a mosquito acquires an infection in the hemocoel, dedicated immune cells called hemocytes aggregate around the valves of the heart. These sessile hemocytes are called periostial hemocytes. In the present study we scrutinized the immune response mounted by the periostial hemocytes of the malaria mosquito, Anopheles gambiae, against bacterial pathogens, and tested the relationship between periostial hemocyte aggregation, immune activity, and hemolymph flow. Initially, we quantified the process of periostial hemocyte aggregation and found that hemocytes migrate to the periostial regions in response to infection with Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, and Micrococcus luteus (all infections tested). Then, we investigated whether the periostial hemocytes are evenly distributed along the six periostial regions of the heart, and found that they preferentially aggregate in the periostial regions of the mid-abdominal segments (4, 5 and 6). This distribution perfectly correlates with the spatial distribution of phagocytic activity along the surface of the heart, and to a lesser extent, with the distribution of melanin deposits. Finally, experiments measuring circulatory physiology found that the majority of hemolymph enters the heart through the ostia located in the periostial regions of abdominal segments 4, 5, and 6. These data show that periostial hemocytes aggregate on the surface of the heart in response to diverse foreign stimuli, and that both hemocytes and immune activity preferentially occur in the regions that experience the swiftest hemolymph flow. Thus, these data show that two major organ systems - the immune and circulatory systems - interact to control infections.
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Affiliation(s)
- Leah T Sigle
- 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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11
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Vantaux A, de Sales Hien DF, Yameogo B, Dabiré KR, Thomas F, Cohuet A, Lefèvre T. Host-seeking behaviors of mosquitoes experimentally infected with sympatric field isolates of the human malaria parasite Plasmodium falciparum: no evidence for host manipulation. Front Ecol Evol 2015. [DOI: 10.3389/fevo.2015.00086] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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12
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Hillyer JF. Integrated Immune and Cardiovascular Function in Pancrustacea: Lessons from the Insects. Integr Comp Biol 2015; 55:843-55. [DOI: 10.1093/icb/icv021] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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13
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Hillyer JF, Strand MR. Mosquito hemocyte-mediated immune responses. CURRENT OPINION IN INSECT SCIENCE 2014; 3:14-21. [PMID: 25309850 PMCID: PMC4190037 DOI: 10.1016/j.cois.2014.07.002] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Hemocytes are a key component of the mosquito immune system that kill pathogens via phagocytic, lytic and melanization pathways. Individual mosquitoes contain between 500 and 4,000 hemocytes, which are divided into three populations named granulocytes, oenocytoids and prohemocytes. Hemocytes can also be divided by their anatomical location with 75% of hemocytes circulating in the hemocoel (circulating hemocytes) and 25% of hemocytes attaching themselves to tissues (sessile hemocytes). Greater than 85% of the hemocytes in adult mosquitoes are granulocytes, which primarily kill pathogens by phagocytosis or lysis. Oenocytoids, on the other hand, are the major producers of the enzymes required for melanization while prohemocytes are small cells that participate in phagocytosis. Both circulating and sessile hemocytes engage in defense against pathogens. The circulatory system of mosquitoes also interacts with hemocytes and facilitates elimination of potential pathogens that enter the hemocoel.
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Affiliation(s)
- Julián F. Hillyer
- Department of Biological Sciences and Institute for Global Health, Vanderbilt University, Nashville, TN, USA
| | - Michael R. Strand
- Department of Entomology and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, USA
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