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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 2024:105219. [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] [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 hr 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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2
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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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3
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Gorges MA, Balko JA, Lathan AW, Gregory TM, Heniff AC, Lewbart GA. DEVELOPMENT OF A HEMOLYMPH COLLECTION TECHNIQUE AND REPORT OF BIOCHEMICAL PARAMETERS OF HEMOLYMPH IN A MANAGED POPULATION OF FEMALE THORNY DEVIL STICK INSECTS ( EURYCANTHA CALCARATA). J Zoo Wildl Med 2024; 55:22-30. [PMID: 38453484 DOI: 10.1638/2023-0063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/23/2023] [Indexed: 03/09/2024] Open
Abstract
Insects are increasingly common in households, zoological collections, research, and food industries. Increased knowledge of insect health parameters is necessary to ensure proper welfare. The study goal was to develop a hemolymph collection technique and report hemolymph serum biochemical parameters for the thorny devil stick insect (Eurycantha calcarata). Clinically healthy adult stick insects (5 males and 14 females, 15.1-24.7 g) were enrolled. Four collection techniques were evaluated. Hemolymph collection was unsuccessful in males, but was successful in females by using a single technique. The insect was manually restrained in an elevated position and an 18-ga × 2.54-cm needle was used to puncture the membrane just caudal to the third pair of legs. With the puncture site directed ventrally, ≤1 ml of hemolymph was collected via gravity and allowed to visibly clot. The sample was then centrifuged, and the serum was separated. Serum samples were individually analyzed (Avian/Reptilian Profile Plus, VetScan VS2, Abaxis, Inc, Union City, CA 94587, USA). Fourteen samples (0.2-1.0 ml) were collected from 14 females. Median (minimum-maximum) parameters included the following: aspartate aminotransferase 12 (0-45) U/L, creatinine kinase 25 (0-76) U/L, uric acid 7.5 (3.1-13.7) mg/dl, glucose 12 (8-22) mg/dl, calcium 18.6 (17.2-19.4) mg/dl, phosphorus 15.0 (n = 1) or >30.0 (n = 13) mg/dL, total protein 2.7 (1.6-2.9) g/dL, albumin 0.9 (0.2-1.2) g/dL, globulin 1.7 (1.6-1.8) g/dL (n = 6) or not quantified (n = 8), potassium 10.6 (9.0-11.8) mmol/L, sodium < 100 mmol/L, and bile acids 0 lmol/L. This is the first report of biochemistry parameters in clinically healthy female stick insects. Larger sample sizes are needed to establish statistically valid reference ranges. Hemolymph collection techniques for male stick insects warrant further investigation.
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Affiliation(s)
- Melinda A Gorges
- Departments of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, USA
| | - Julie A Balko
- Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, USA,
| | - Andrew W Lathan
- Departments of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, USA
| | - Taylor M Gregory
- Departments of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, USA
| | - Ashlyn C Heniff
- Departments of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, USA
| | - Gregory A Lewbart
- Departments of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, USA
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4
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Lin CY, Zhang YM, Li BZ, Shu MA, Xu WB. Identification and characterization of mitogen-activated protein kinase kinase 4 (MKK4) from the mud crab Scylla paramamosain in response to Vibrio alginolyticus and White Spot Syndrome Virus (WSSV). DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2023; 147:104755. [PMID: 37295629 DOI: 10.1016/j.dci.2023.104755] [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: 03/07/2023] [Revised: 06/03/2023] [Accepted: 06/07/2023] [Indexed: 06/12/2023]
Abstract
Mitogen-activated protein kinase kinase 4 (MKK4), serves as a critical component of the mitogen-activated protein kinase signaling pathway, facilitating the direct phosphorylation and activation of the c-Jun N-terminal kinase (JNK) and p38 families of MAP kinases in response to environmental stresses. In the current research, we identified two MKK4 subtypes, namely SpMKK4-1 and SpMKK4-2, from Scylla paramamosain, followed by the analysis of their molecular characteristics and tissue distributions. The expression of SpMKK4s was induced upon WSSV and Vibrio alginolyticus challenges, and the bacteria clearance capacity and antimicrobial peptide (AMP) genes' expression upon bacterial infection were significantly decreased after knocking down SpMKK4s. Additionally, the overexpression of both SpMKK4s remarkably activated NF-κB reporter plasmid in HEK293T cells, suggesting the activation of the NF-κB signaling pathway. These results indicated the participation of SpMKK4s in the innate immunity of crabs, which shed light on a better understanding of the mechanisms through which MKK4s regulate innate immunity.
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Affiliation(s)
- Chen-Yang Lin
- College of Animal Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Yan-Mei Zhang
- College of Animal Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Bang-Ze Li
- College of Animal Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Miao-An Shu
- College of Animal Sciences, Zhejiang University, Hangzhou, 310058, China.
| | - Wen-Bin Xu
- College of Animal Sciences, Zhejiang University, Hangzhou, 310058, China.
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5
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Cardoso-Jaime V, Maya-Maldonado K, Tsutsumi V, Hernández-Martínez S. Mosquito pericardial cells upregulate Cecropin expression after an immune challenge. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2023; 147:104745. [PMID: 37268262 DOI: 10.1016/j.dci.2023.104745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 05/23/2023] [Accepted: 05/24/2023] [Indexed: 06/04/2023]
Abstract
Most mosquito-transmitted pathogens grow or replicate in the midgut before invading the salivary glands. Pathogens are exposed to several immunological factors along the way. Recently, it was shown that hemocytes gather near the periostial region of the heart to efficiently phagocytose pathogens circulating in the hemolymph. Nerveless, not all pathogens can be phagocyted by hemocytes and eliminated by lysis. Interestingly, some studies have shown that pericardial cells (PCs) surrounding periostial regions, may produce humoral factors, such as lysozymes. Our current work provides evidence that Anopheles albimanus PCs are a major producer of Cecropin 1 (Cec1). Furthermore, our findings reveal that after an immunological challenge, PCs upregulate Cec1 expression. We conclude that PCs are positioned in a strategic location that could allow releasing humoral components, such as cecropin, to lyse pathogens on the heart or circulating in the hemolymph, implying that PCs could play a significant role in the systemic immune response.
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Affiliation(s)
- Victor Cardoso-Jaime
- Centro de Investigaciones Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública. Av. Universidad 655, Santa María Ahuacatitlan, Cuernavaca, Morelos, C.P. 62100, Mexico; Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados, IPN. Av. Instituto Politécnico Nacional 2508, Gustavo A. Madero, Ciudad de México, C.P. 07360, Mexico
| | - Krystal Maya-Maldonado
- Centro de Investigaciones Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública. Av. Universidad 655, Santa María Ahuacatitlan, Cuernavaca, Morelos, C.P. 62100, Mexico; Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados, IPN. Av. Instituto Politécnico Nacional 2508, Gustavo A. Madero, Ciudad de México, C.P. 07360, Mexico
| | - Víctor Tsutsumi
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados, IPN. Av. Instituto Politécnico Nacional 2508, Gustavo A. Madero, Ciudad de México, C.P. 07360, Mexico.
| | - Salvador Hernández-Martínez
- Centro de Investigaciones Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública. Av. Universidad 655, Santa María Ahuacatitlan, Cuernavaca, Morelos, C.P. 62100, Mexico.
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6
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Rauniyar K, Bokharaie H, Jeltsch M. Expansion and collapse of VEGF diversity in major clades of the animal kingdom. Angiogenesis 2023; 26:437-461. [PMID: 37017884 PMCID: PMC10328876 DOI: 10.1007/s10456-023-09874-9] [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: 01/20/2023] [Accepted: 03/17/2023] [Indexed: 04/06/2023]
Abstract
Together with the platelet-derived growth factors (PDGFs), the vascular endothelial growth factors (VEGFs) form the PDGF/VEGF subgroup among cystine knot growth factors. The evolutionary relationships within this subgroup have not been examined thoroughly to date. Here, we comprehensively analyze the PDGF/VEGF growth factors throughout all animal phyla and propose a phylogenetic tree. Vertebrate whole-genome duplications play a role in expanding PDGF/VEGF diversity, but several limited duplications are necessary to account for the temporal pattern of emergence. The phylogenetically oldest PDGF/VEGF-like growth factor likely featured a C-terminus with a BR3P signature, a hallmark of the modern-day lymphangiogenic growth factors VEGF-C and VEGF-D. Some younger VEGF genes, such as VEGFB and PGF, appeared completely absent in important vertebrate clades such as birds and amphibia, respectively. In contrast, individual PDGF/VEGF gene duplications frequently occurred in fish on top of the known fish-specific whole-genome duplications. The lack of precise counterparts for human genes poses limitations but also offers opportunities for research using organisms that diverge considerably from humans. Sources for the graphical abstract: 326 MYA and older [1]; 72-240 MYA [2]; 235-65 MYA [3].
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Affiliation(s)
- Khushbu Rauniyar
- Drug Research Program, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Biocenter 2, (Viikinkaari 5E), P.O. Box. 56, 00790, Helsinki, Finland
| | - Honey Bokharaie
- Drug Research Program, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Biocenter 2, (Viikinkaari 5E), P.O. Box. 56, 00790, Helsinki, Finland
| | - Michael Jeltsch
- Drug Research Program, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Biocenter 2, (Viikinkaari 5E), P.O. Box. 56, 00790, Helsinki, Finland.
- Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
- Wihuri Research Institute, Helsinki, Finland.
- Helsinki One Health, University of Helsinki, Helsinki, Finland.
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7
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Fellows CJ, Simone-Finstrom M, Anderson TD, Swale DR. Potassium ion channels as a molecular target to reduce virus infection and mortality of honey bee colonies. Virol J 2023; 20:134. [PMID: 37349817 PMCID: PMC10286336 DOI: 10.1186/s12985-023-02104-0] [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: 05/01/2023] [Accepted: 06/16/2023] [Indexed: 06/24/2023] Open
Abstract
Declines in managed honey bee populations are multifactorial but closely associated with reduced virus immunocompetence and thus, mechanisms to enhance immune function are likely to reduce viral infection rates and increase colony viability. However, gaps in knowledge regarding physiological mechanisms or 'druggable' target sites to enhance bee immunocompetence has prevented therapeutics development to reduce virus infection. Our data bridge this knowledge gap by identifying ATP-sensitive inward rectifier potassium (KATP) channels as a pharmacologically tractable target for reducing virus-mediated mortality and viral replication in bees, as well as increasing an aspect of colony-level immunity. Bees infected with Israeli acute paralysis virus and provided KATP channel activators had similar mortality rates as uninfected bees. Furthermore, we show that generation of reactive oxygen species (ROS) and regulation of ROS concentrations through pharmacological activation of KATP channels can stimulate antiviral responses, highlighting a functional framework for physiological regulation of the bee immune system. Next, we tested the influence of pharmacological activation of KATP channels on infection of 6 viruses at the colony level in the field. Data strongly support that KATP channels are a field-relevant target site as colonies treated with pinacidil, a KATP channel activator, had reduced titers of seven bee-relevant viruses by up to 75-fold and reduced them to levels comparable to non-inoculated colonies. Together, these data indicate a functional linkage between KATP channels, ROS, and antiviral defense mechanisms in bees and define a toxicologically relevant pathway that can be used for novel therapeutics development to enhance bee health and colony sustainability in the field.
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Affiliation(s)
- Christopher J Fellows
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA, 70803, USA
| | - Michael Simone-Finstrom
- USDA-ARS Honey Bee Breeding, Genetics, and Physiology Laboratory, Baton Rouge, LA, 70820, USA
| | - Troy D Anderson
- Department of Entomology, University of Nebraska, Lincoln, NE, 68583, USA
| | - Daniel R Swale
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA, 70803, USA.
- Department of Entomology and Nematology, Emerging Pathogens Institute, University of Florida, 2055 Mowry Road, PO Box 100009, Gainesville, FL, 32610, USA.
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8
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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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9
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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: 5] [Impact Index Per Article: 2.5] [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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10
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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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11
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Kotlyarov S. Immune Function of Endothelial Cells: Evolutionary Aspects, Molecular Biology and Role in Atherogenesis. Int J Mol Sci 2022; 23:ijms23179770. [PMID: 36077168 PMCID: PMC9456046 DOI: 10.3390/ijms23179770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 08/23/2022] [Accepted: 08/25/2022] [Indexed: 11/16/2022] Open
Abstract
Atherosclerosis is one of the key problems of modern medicine, which is due to the high prevalence of atherosclerotic cardiovascular diseases and their significant share in the structure of morbidity and mortality in many countries. Atherogenesis is a complex chain of events that proceeds over many years in the vascular wall with the participation of various cells. Endothelial cells are key participants in vascular function. They demonstrate involvement in the regulation of vascular hemodynamics, metabolism, and innate immunity, which act as leading links in the pathogenesis of atherosclerosis. These endothelial functions have close connections and deep evolutionary roots, a better understanding of which will improve the prospects of early diagnosis and effective treatment.
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Affiliation(s)
- Stanislav Kotlyarov
- Department of Nursing, Ryazan State Medical University, 390026 Ryazan, Russia
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12
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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: 0] [Impact Index Per Article: 0] [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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Duneau D, Ferdy JB. Pathogen within-host dynamics and disease outcome: what can we learn from insect studies? CURRENT OPINION IN INSECT SCIENCE 2022; 52:100925. [PMID: 35489681 DOI: 10.1016/j.cois.2022.100925] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 04/13/2022] [Accepted: 04/19/2022] [Indexed: 06/14/2023]
Abstract
Parasite proliferations within/on the host form the basis of the outcome of all infectious diseases. However, within-host dynamics are difficult to study in vertebrates, as it requires regularly following pathogen proliferation from the start of the infection and at the organismal level. Invertebrate models allow for this monitoring under controlled conditions using population approaches. These approaches offer the possibility to describe many parameters of the within-host dynamics, such as rate of proliferation, probability to control the infection, and average time at which the pathogen is controlled. New parameters such as the Pathogen Load Upon Death and the Set-Point Pathogen Load have emerged to characterize within-host dynamics and better understand disease outcome. While contextualizing the potential of studying within-host dynamics in insects to build fundamental knowledge, we review what we know about within-host dynamics using insect models, and what it can offer to our knowledge of infectious diseases.
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Affiliation(s)
- David Duneau
- Université Toulouse 3 Paul Sabatier, CNRS, IRD, UMR5174 EDB (Laboratoire Évolution & Diversité Biologique), Toulouse, France; Instituto Gulbenkian de Ciência, Rua da Quinta Grande 6, P-2780 Oeiras, Portugal.
| | - Jean-Baptiste Ferdy
- Université Toulouse 3 Paul Sabatier, CNRS, IRD, UMR5174 EDB (Laboratoire Évolution & Diversité Biologique), Toulouse, France.
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Identification of the Gene Repertoire of the IMD Pathway and Expression of Antimicrobial Peptide Genes in Several Tissues and Hemolymph of the Cockroach Blattella germanica. Int J Mol Sci 2022; 23:ijms23158444. [PMID: 35955579 PMCID: PMC9369362 DOI: 10.3390/ijms23158444] [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] [Received: 06/22/2022] [Revised: 07/26/2022] [Accepted: 07/28/2022] [Indexed: 02/05/2023] Open
Abstract
Antimicrobial peptide (AMP) genes, triggered by Toll and IMD pathways, are essential components of the innate immune system in the German cockroach Blattella germanica. Besides their role in killing pathogenic bacteria, AMPs could be involved in controlling its symbiotic systems (endosymbiont and microbiota). We found that the IMD pathway was active in the adult female transcriptomes of six tissues (salivary glands, foregut, midgut, hindgut, Malpighian tubules and fat body) and hemolymph. Total expression of AMP genes was high in hemolymph and salivary glands and much lower in the other sample types. The expression of specific AMP genes was very heterogeneous among sample types. Two genes, defensin_g10 and drosomycin_g5, displayed relevant expression in the seven sample types, although higher in hemolymph. Other genes only displayed high expression in one tissue. Almost no expression of attacin-like and blattellicin genes was observed in any sample type, although some of them were among the genes with the highest expression in adult female whole bodies. The expression of AMP genes in salivary glands could help control pathogens ingested with food and even determine gut microbiota composition. The low expression levels in midgut and hindgut are probably related to the presence of beneficial microbiota. Furthermore, a reduction in the expression of AMP genes in fat body could be the way to prevent damage to the population of the endosymbiont Blattabacterium cuenoti within bacteriocytes.
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Silencing Transglutaminase Genes TGase2 and TGase3 Has Infection-Dependent Effects on the Heart Rate of the Mosquito Anopheles gambiae. INSECTS 2022; 13:insects13070582. [PMID: 35886758 PMCID: PMC9315499 DOI: 10.3390/insects13070582] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [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
Simple Summary The immune and circulatory systems of insects are functionally integrated. An infection induces the migration of immune cells called hemocytes to the surface of the heart, where they kill pathogens around valves called ostia. In mosquitoes, a transglutaminase inhibits the infection-induced aggregation of hemocytes on the heart. Here, we studied whether transglutaminases also modify the heart contraction rate. First, we confirmed that an infection decreases the mosquito heart rate. Then, we found that disrupting transglutaminase genes has infection-dependent effects on the heart rate. Silencing TGase1 does not affect heart physiology. However, silencing TGase2 eliminates the infection-induced decrease in the heart rate, and silencing TGase3 decreases the heart rate in uninfected mosquitoes but increases the heart rate in infected mosquitoes. These experiments identify new factors that affect heart physiology in mosquitoes. 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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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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Lee J, Cha WH, Lee DW. Multiple Precursor Proteins of Thanatin Isoforms, an Antimicrobial Peptide Associated With the Gut Symbiont of Riptortus pedestris. Front Microbiol 2022; 12:796548. [PMID: 35069496 PMCID: PMC8767025 DOI: 10.3389/fmicb.2021.796548] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 12/10/2021] [Indexed: 01/08/2023] Open
Abstract
Thanatin is an antimicrobial peptide (AMP) generated by insects for defense against bacterial infections. In the present study, we performed cDNA cloning of thanatin and found the presence of multiple precursor proteins from the bean bug, Riptortus pedestris. The cDNA sequences encoded 38 precursor proteins, generating 13 thanatin isoforms. In the phylogenetic analysis, thanatin isoforms were categorized into two groups based on the presence of the membrane attack complex/perforin (MACPF) domain. In insect-bacterial symbiosis, specific substances are produced by the immune system of the host insect and are known to modulate the symbiont’s population. Therefore, to determine the biological function of thanatin isoforms in symbiosis, the expression levels of three AMP genes were compared between aposymbiotic insects and symbiotic R. pedestris. The expression levels of the thanatin genes were significantly increased in the M4 crypt, a symbiotic organ, of symbiotic insects upon systemic bacterial injection. Further, synthetic thanatin isoforms exhibited antibacterial activity against gut-colonized Burkholderia symbionts rather than in vitro-cultured Burkholderia cells. Interestingly, the suppression of thanatin genes significantly increased the population of Burkholderia gut symbionts in the M4 crypt under systemic Escherichia coli K12 injection. Overgrown Burkholderia gut symbionts were observed in the hemolymph of host insects and exhibited insecticidal activity. Taken together, these results suggest that thanatin of R. pedestris is a host-derived symbiotic factor and an AMP that controls the population of gut-colonized Burkholderia symbionts.
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Affiliation(s)
- Junbeom Lee
- Metabolomics Research Center for Functional Materials, Kyungsung University, Busan, South Korea
| | - Wook Hyun Cha
- Department of Bio-Safety, Kyungsung University, Busan, South Korea
| | - Dae-Weon Lee
- Metabolomics Research Center for Functional Materials, Kyungsung University, Busan, South Korea.,Department of Bio-Safety, Kyungsung University, Busan, South Korea
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Strachecka A, Migdał P, Kuszewska K, Skowronek P, Grabowski M, Paleolog J, Woyciechowski M. Humoral and Cellular Defense Mechanisms in Rebel Workers of Apis mellifera. BIOLOGY 2021; 10:1146. [PMID: 34827139 PMCID: PMC8615136 DOI: 10.3390/biology10111146] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/03/2021] [Accepted: 11/03/2021] [Indexed: 12/20/2022]
Abstract
The physiological state of an insect depends on efficiently functioning immune mechanisms such as cellular and humoral defenses. However, compounds participating in these mechanisms also regulate reproductive caste formation and are responsible for reproductive division of labor as well as for labor division in sterile workers. Divergent reaction of the same genotype yielding reproductive queens and worker castes led to shaping of the physiological and behavioral plasticity of sterile or reproductive workers. Rebels that can lay eggs while maintaining tasks inside and outside the colony exhibit both queen and worker traits. So, we expected that the phagocytic index, JH3 titer, and Vg concentration would be higher in rebels than in normal workers and would increase with their age. We also assumed that the numbers of oenocytes and their sizes would be greater in rebels than in normal workers. The rebels and the normal workers were collected at the age of 1, 7, 14, and 21 days, respectively. Hemolymph and fat bodies were collected for biochemical and morphological analyses. The high levels of JH, Vg, and the phagocytic index, as well as increased numbers and sizes of oenocytes in the fat body cells demonstrate the physiological and phenotypic adaptation of rebels to the eusocial life of honeybees.
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Affiliation(s)
- Aneta Strachecka
- Department of Invertebrate Ecophysiology and Experimental Biology, University of Life Sciences in Lublin, 20-950 Lublin, Poland; (P.S.); (M.G.); (J.P.)
| | - Paweł Migdał
- Department of Environment, Hygiene and Animal Welfare, Wroclaw University of Environmental and Life Sciences, 50-375 Wroclaw, Poland;
| | - Karolina Kuszewska
- Institute of Environmental Sciences, Jagiellonian University, 30-387 Krakow, Poland; (K.K.); (M.W.)
| | - Patrycja Skowronek
- Department of Invertebrate Ecophysiology and Experimental Biology, University of Life Sciences in Lublin, 20-950 Lublin, Poland; (P.S.); (M.G.); (J.P.)
| | - Marcin Grabowski
- Department of Invertebrate Ecophysiology and Experimental Biology, University of Life Sciences in Lublin, 20-950 Lublin, Poland; (P.S.); (M.G.); (J.P.)
| | - Jerzy Paleolog
- Department of Invertebrate Ecophysiology and Experimental Biology, University of Life Sciences in Lublin, 20-950 Lublin, Poland; (P.S.); (M.G.); (J.P.)
| | - Michał Woyciechowski
- Institute of Environmental Sciences, Jagiellonian University, 30-387 Krakow, Poland; (K.K.); (M.W.)
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Boulet M, Renaud Y, Lapraz F, Benmimoun B, Vandel L, Waltzer L. Characterization of the Drosophila Adult Hematopoietic System Reveals a Rare Cell Population With Differentiation and Proliferation Potential. Front Cell Dev Biol 2021; 9:739357. [PMID: 34722521 PMCID: PMC8550105 DOI: 10.3389/fcell.2021.739357] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 09/22/2021] [Indexed: 02/06/2023] Open
Abstract
While many studies have described Drosophila embryonic and larval blood cells, the hematopoietic system of the imago remains poorly characterized and conflicting data have been published concerning adult hematopoiesis. Using a combination of blood cell markers, we show that the adult hematopoietic system is essentially composed of a few distinct mature blood cell types. In addition, our transcriptomics results indicate that adult and larval blood cells have both common and specific features and it appears that adult hemocytes reactivate many genes expressed in embryonic blood cells. Interestingly, we identify a small set of blood cells that does not express differentiation markers but rather maintains the expression of the progenitor marker domeMeso. Yet, we show that these cells are derived from the posterior signaling center, a specialized population of cells present in the larval lymph gland, rather than from larval blood cell progenitors, and that their maintenance depends on the EBF transcription factor Collier. Furthermore, while these cells are normally quiescent, we find that some of them can differentiate and proliferate in response to bacterial infection. In sum, our results indicate that adult flies harbor a small population of specialized cells with limited hematopoietic potential and further support the idea that no substantial hematopoiesis takes place during adulthood.
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Affiliation(s)
- Manon Boulet
- Université Clermont Auvergne, Centre National de la Recherche Scientifique, Institut National de la Sante et de la Recherche Medicale, Institut Génétique Reproduction et Développement, Clermont-Ferrand, France
| | - Yoan Renaud
- Université Clermont Auvergne, Centre National de la Recherche Scientifique, Institut National de la Sante et de la Recherche Medicale, Institut Génétique Reproduction et Développement, Clermont-Ferrand, France
| | - François Lapraz
- Centre de Biologie du Développement, Centre de Biologie Intégrative, Université de Toulouse, Centre National de la Recherche Scientifique, Université Paul Sabatier, Toulouse, France
| | - Billel Benmimoun
- Centre de Biologie du Développement, Centre de Biologie Intégrative, Université de Toulouse, Centre National de la Recherche Scientifique, Université Paul Sabatier, Toulouse, France
| | - Laurence Vandel
- Université Clermont Auvergne, Centre National de la Recherche Scientifique, Institut National de la Sante et de la Recherche Medicale, Institut Génétique Reproduction et Développement, Clermont-Ferrand, France
| | - Lucas Waltzer
- Université Clermont Auvergne, Centre National de la Recherche Scientifique, Institut National de la Sante et de la Recherche Medicale, Institut Génétique Reproduction et Développement, Clermont-Ferrand, France.,Centre de Biologie du Développement, Centre de Biologie Intégrative, Université de Toulouse, Centre National de la Recherche Scientifique, Université Paul Sabatier, Toulouse, France
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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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Rodríguez M, Pagola L, Norry FM, Ferrero P. Cardiac performance in heat-stressed flies of heat-susceptible and heat-resistant Drosophila melanogaster. JOURNAL OF INSECT PHYSIOLOGY 2021; 133:104268. [PMID: 34171365 DOI: 10.1016/j.jinsphys.2021.104268] [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: 02/09/2021] [Revised: 05/24/2021] [Accepted: 06/17/2021] [Indexed: 06/13/2023]
Abstract
Thermotolerance is a complex trait that can greatly differ between heat-susceptible (HS) and heat-adapted populations of small insects including Drosophila, with short-term effects after a sub-lethal level of heat stress on many physiological functions. Cardiac performance could accordingly be more robust in heat-resistant (HR) than in HS individuals under heat stress. Here, we tested heart performance under heat-stress effects in two recombinant inbred lines (RIL) of Drosophila melanogaster that dramatically differ in heat knockdown resistance. Heart rate did not strongly differ between heat-susceptible and heat-tolerant flies after a sub-lethal heat stress. Instead, heat-susceptible flies showed a much higher arrhythmia incidence, a longer duration of each heartbeat, and a larger amount of bradycardia than heat-tolerant flies. The highly conserved cardiac proteins SERCA, RyR and NCX that participate in the excitation/contraction coupling, did not differ in activity level between HR and HS flies. Available information for both RIL suggests that heart performance under heat stress may be linked, at least partially, to candidate genes of previously identified quantitative trait loci (QTL) for thermotolerance. This study indicates that HR flies can be genetically more robust in their heart performance than HS flies under even sub-lethal levels of heat stress.
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Affiliation(s)
- Maia Rodríguez
- Departamento de Ciencias Básicas y Experimentales, Universidad Nacional del Noroeste de la Provincia de Buenos Aires, Pergamino 2700, Buenos Aires, Argentina
| | - Lucía Pagola
- Centro de Investigaciones Cardiovasculares 'Dr. Horacio E. Cingolani', Facultad de Ciencias Médicas, UNLP, La Plata 1900, Buenos Aires, Argentina
| | - Fabian M Norry
- Facultad de Ciencias Exactas y Naturales, Departamento de Ecología, Genética y Evolución, Universidad de Buenos Aires, C-1428-EHA Buenos Aires, Argentina; Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA) - CONICET, Universidad de Buenos Aires, C-1428-EHA Buenos Aires, Argentina.
| | - Paola Ferrero
- Departamento de Ciencias Básicas y Experimentales, Universidad Nacional del Noroeste de la Provincia de Buenos Aires, Pergamino 2700, Buenos Aires, Argentina; Centro de Investigaciones Cardiovasculares 'Dr. Horacio E. Cingolani', Facultad de Ciencias Médicas, UNLP, La Plata 1900, Buenos Aires, Argentina.
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