Insect hemocytes play important biological roles at developmental stages,metamorphosis,and innate immunity.As one of the most abundant cell types,plasmatocytes can participate in various innate immune responses,especi...Insect hemocytes play important biological roles at developmental stages,metamorphosis,and innate immunity.As one of the most abundant cell types,plasmatocytes can participate in various innate immune responses,especially in encapsulation and node formation.Here,2 molecular markers of plasmatocytes,consisting of integrinβ2 andβ3,were identified and used to understand the development of plasmatocytes.Plasmatocytes are widely distributed in the hematopoietic system,including circulating hemolymph and hematopoietic organs(HPOs).HPOs constantly release plasmatocytes with high proliferative activity in vitro;removal of HPOs leads to a dramatic reduction in the circulating plasmatocytes,and the remaining plasmatocytes gradually lose their ability to proliferate in vivo.Our results demonstrated that the release of plasmatocytes from HPOs is regulated by insulin-mediated signals and their downstream pathways,including PI3K/Akt and MAPK/Erk signals.The insulin/PI3K/Akt signaling pathway can significantly irritate the hematopoiesis,and its inhibitor LY294002 could inhibit the hemocytes discharged from HPOs.While the insulin/MAPK/Erk signaling pathway plays a negative regulatory role,inhibiting its activity with U0126 can markedly promote the discharge of plasmatocytes from HPOs.Our results indicate that the circulating plasmatocytes are mainly generated and discharged by HPOs.This process is co-regulated by the PI3K/Akt and MAPK/Erk signals in an antagonistic manner to adjust the dynamic balance of the hemocytes.These findings can enhance our understanding of insect hematopoiesis.展开更多
Drosophila has been extensively used to model the human blood-immune system,as both systems share many developmental and immune response mechanisms.However,while many human blood cell types have been identified,only t...Drosophila has been extensively used to model the human blood-immune system,as both systems share many developmental and immune response mechanisms.However,while many human blood cell types have been identified,only three were found in flies:plasmatocytes,crystal cells and lamellocytes.To better understand the complexity of fly blood system,we used single-cell RNA sequencing technology to generate co mprehensive gene expression profiles for Drosophila circulating blood cells.In addition to the known cell types,we identified two new Drosophila blood cell types:thanacytes and primocytes.Thanacytes,which express many stimulus response genes,are involved in distinct responses to different types of bacteria.Primocytes,which express cell fate commitment and signaling genes,appear to be involved in keeping stem cells in the circulating blood.Furthermore,our data revealed four novel plasmatocyte subtypes(Ppn+,CAH7^+,Lsp^+and reservoir plasmatocytes),each with unique molecular identities and distinct predicted functions.We also identified cross-species markers from Drosophila hemocytes to human blood cells.Our analysis unveiled a more complex Drosophila blood system and broadened the scope of using Drosophila to model human blood system in development and disease.展开更多
Innate immunity is essential for the wellbeing of vertebrates and invertebrates. Key components of this defense system include pattern recognition receptors that bind to infectious agents, extra-and intra-cellular pro...Innate immunity is essential for the wellbeing of vertebrates and invertebrates. Key components of this defense system include pattern recognition receptors that bind to infectious agents, extra-and intra-cellular proteins that relay signals, as well as molecules and cells that eliminate pathogens. We have been studying the defense mechanisms in a biochemical model insect, Manduca sexta. In this insect, hemolin, peptidoglycan recognition proteins, β-1,3-glucan recognition proteins and C-type lectins detect microbial surface molecules and induce immune responses such as phagocytosis, nodulation, encapsulation, melanization and production of antimicrobial peptides. Some of these responses are mediated by extracellular serine proteinase pathways. The proteolytic activation of prophenoloxidase （proPO） yields active phenoloxidase （PO） which catalyzes the formation of quinones and melanin for wound healing and microbe killing. M. sexta hemolymph proteinase 14 （HP 14） precursor interacts with peptidoglycan or β-1,3-glucan, autoactivates, and leads to the activation of other HPs including HP21 and proPO-activating proteinases （PAPs）. PAP-1, -2 and -3 cut proPO to generate active PO in the presence of two serine proteinase homologs. Inhibition of the proteinases by serpins and association of the proteinase homologs with bacteria ensure a localized defense reaction. M. sexta HP1, HP6, HP8, HP17 and other proteinases may also participate in proPO activation or processing of spatzle and plasmatocyte spreading peptide.展开更多
Granulocytes and plasmatocytes play important roles in clearing foreign objects in insects,but it is difficult to distinguish between them in immune reactions.Based on the hemocyte cell line SYSU-OfHe-C established at...Granulocytes and plasmatocytes play important roles in clearing foreign objects in insects,but it is difficult to distinguish between them in immune reactions.Based on the hemocyte cell line SYSU-OfHe-C established at our lab,two cell sublines,SYSU-OfHe-C Granulocyte(Gr cells)and SYSU-OHe-C Plasmatocyte(PI cells),which possess the morphological characteristics of granulocytes and plasmatocytes,respectively,were established.Gr and PI cells showed different behaviors in immune reactions,such as spreading,phagocytosis and encapsulation.PI cells were easier to spread,but Gr cells tended to undergo aggregation,indicating that they may take different strategies to clear foreign objects.These results also suggested that granulocytes and plasmatocytes may express some different proteins.By comparing the gene expression in cells from the two sublines,1662 differentially expressed genes were identified,and 13 out of 30 transmembrane proteins highly ex pressed in PI cells(six)or Gr cells(seven)were further screened and confirmed by reverse-transcription polymerase chain reaction(PCR).Finally,three transmembrane genes specifically expressed in Pl cells and two transmembrane genes specifically expressed in Gr cells were screened out based on their expressions in immune reactions by quantitative PCR analysis.These genes may potentially be used as molecular markers to distinguish between granulocy tes and plasmatocytes in Ostrinia fiurnacalis,and further to clarify the functions of immune hemocytes in cellular immune reaction such as encapsulation and so on.展开更多
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 ...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.展开更多
Macrophages are well known for their phagocytic functions in innate immunity across species.In mammals,they rapidly consume a large amount of energy by shifting their metabolism from mitochondrial oxidative phosphoryl...Macrophages are well known for their phagocytic functions in innate immunity across species.In mammals,they rapidly consume a large amount of energy by shifting their metabolism from mitochondrial oxidative phosphorylation toward aerobic glycolysis,to perform the effective bactericidal function upon infection.Meanwhile,they strive for sufficient energy resources by restricting systemic metabolism.In contrast,under nutrient deprivation,the macrophage population is down-regulated to save energy for survival.Drosophila melanogaster possesses a highly conserved and comparatively simple innate immune system.Intriguingly,recent studies have shown that Drosophila plasmatocytes,the macrophage-like blood cells,adopt comparable metabolic remodeling and signaling pathways to achieve energy reassignment when challenged by pathogens,indicating the conservation of such metabolic strategies between insects and mammals.Here,focusing on Drosophila macrophages(plasmatocytes),we review recent advances regarding their comprehensive roles in local or systemic metabolism under homeostasis or stress,emphasizing macrophages as critical players in the crosstalk between the immune system and organic metabolism from a Drosophila perspective.展开更多
基金supported by the National Natural Science Foundation of China(31802142)the Doctoral Start-up Fund of the Southwest University(SWU120019)+1 种基金the F undamental Research Funds for the Central Universi-ties(XDJK2019C089)the project funded by the China Postdoctoral Science Foundation(2019T120801 and 2017M620408).
文摘Insect hemocytes play important biological roles at developmental stages,metamorphosis,and innate immunity.As one of the most abundant cell types,plasmatocytes can participate in various innate immune responses,especially in encapsulation and node formation.Here,2 molecular markers of plasmatocytes,consisting of integrinβ2 andβ3,were identified and used to understand the development of plasmatocytes.Plasmatocytes are widely distributed in the hematopoietic system,including circulating hemolymph and hematopoietic organs(HPOs).HPOs constantly release plasmatocytes with high proliferative activity in vitro;removal of HPOs leads to a dramatic reduction in the circulating plasmatocytes,and the remaining plasmatocytes gradually lose their ability to proliferate in vivo.Our results demonstrated that the release of plasmatocytes from HPOs is regulated by insulin-mediated signals and their downstream pathways,including PI3K/Akt and MAPK/Erk signals.The insulin/PI3K/Akt signaling pathway can significantly irritate the hematopoiesis,and its inhibitor LY294002 could inhibit the hemocytes discharged from HPOs.While the insulin/MAPK/Erk signaling pathway plays a negative regulatory role,inhibiting its activity with U0126 can markedly promote the discharge of plasmatocytes from HPOs.Our results indicate that the circulating plasmatocytes are mainly generated and discharged by HPOs.This process is co-regulated by the PI3K/Akt and MAPK/Erk signals in an antagonistic manner to adjust the dynamic balance of the hemocytes.These findings can enhance our understanding of insect hematopoiesis.
基金supported by grants from NIH to Z.H.(R01-HL134940,R01-DK098410)。
文摘Drosophila has been extensively used to model the human blood-immune system,as both systems share many developmental and immune response mechanisms.However,while many human blood cell types have been identified,only three were found in flies:plasmatocytes,crystal cells and lamellocytes.To better understand the complexity of fly blood system,we used single-cell RNA sequencing technology to generate co mprehensive gene expression profiles for Drosophila circulating blood cells.In addition to the known cell types,we identified two new Drosophila blood cell types:thanacytes and primocytes.Thanacytes,which express many stimulus response genes,are involved in distinct responses to different types of bacteria.Primocytes,which express cell fate commitment and signaling genes,appear to be involved in keeping stem cells in the circulating blood.Furthermore,our data revealed four novel plasmatocyte subtypes(Ppn+,CAH7^+,Lsp^+and reservoir plasmatocytes),each with unique molecular identities and distinct predicted functions.We also identified cross-species markers from Drosophila hemocytes to human blood cells.Our analysis unveiled a more complex Drosophila blood system and broadened the scope of using Drosophila to model human blood system in development and disease.
文摘Innate immunity is essential for the wellbeing of vertebrates and invertebrates. Key components of this defense system include pattern recognition receptors that bind to infectious agents, extra-and intra-cellular proteins that relay signals, as well as molecules and cells that eliminate pathogens. We have been studying the defense mechanisms in a biochemical model insect, Manduca sexta. In this insect, hemolin, peptidoglycan recognition proteins, β-1,3-glucan recognition proteins and C-type lectins detect microbial surface molecules and induce immune responses such as phagocytosis, nodulation, encapsulation, melanization and production of antimicrobial peptides. Some of these responses are mediated by extracellular serine proteinase pathways. The proteolytic activation of prophenoloxidase （proPO） yields active phenoloxidase （PO） which catalyzes the formation of quinones and melanin for wound healing and microbe killing. M. sexta hemolymph proteinase 14 （HP 14） precursor interacts with peptidoglycan or β-1,3-glucan, autoactivates, and leads to the activation of other HPs including HP21 and proPO-activating proteinases （PAPs）. PAP-1, -2 and -3 cut proPO to generate active PO in the presence of two serine proteinase homologs. Inhibition of the proteinases by serpins and association of the proteinase homologs with bacteria ensure a localized defense reaction. M. sexta HP1, HP6, HP8, HP17 and other proteinases may also participate in proPO activation or processing of spatzle and plasmatocyte spreading peptide.
基金the National Key R&D Program of China(2017YFD200400)Guangdong Basic and Applied Basic Research Foundation(2020A 1515010455)+2 种基金the National Natural Science Foundation of China(31272091)the Key Project of Chinese National Programs for Fundamental Research and Development(973 programs,2013CB 127603)the International Foundation for Scicncc(C3680-2).
文摘Granulocytes and plasmatocytes play important roles in clearing foreign objects in insects,but it is difficult to distinguish between them in immune reactions.Based on the hemocyte cell line SYSU-OfHe-C established at our lab,two cell sublines,SYSU-OfHe-C Granulocyte(Gr cells)and SYSU-OHe-C Plasmatocyte(PI cells),which possess the morphological characteristics of granulocytes and plasmatocytes,respectively,were established.Gr and PI cells showed different behaviors in immune reactions,such as spreading,phagocytosis and encapsulation.PI cells were easier to spread,but Gr cells tended to undergo aggregation,indicating that they may take different strategies to clear foreign objects.These results also suggested that granulocytes and plasmatocytes may express some different proteins.By comparing the gene expression in cells from the two sublines,1662 differentially expressed genes were identified,and 13 out of 30 transmembrane proteins highly ex pressed in PI cells(six)or Gr cells(seven)were further screened and confirmed by reverse-transcription polymerase chain reaction(PCR).Finally,three transmembrane genes specifically expressed in Pl cells and two transmembrane genes specifically expressed in Gr cells were screened out based on their expressions in immune reactions by quantitative PCR analysis.These genes may potentially be used as molecular markers to distinguish between granulocy tes and plasmatocytes in Ostrinia fiurnacalis,and further to clarify the functions of immune hemocytes in cellular immune reaction such as encapsulation and so on.
基金We wish to thank Prof.Herwig Gutzeit for valuable discussions and providing antibody stocks.We would like to express our gratitude to Dr.Alexander Froschauer and Prof.Klaus Reinhardt who hosted the work in their laboratories,to Prof.Thorsten Mascher and Prof.Christian Dahmann for allowing us to use their laboratory equipment,and Dr.Diana Wolf who provided bacteria strains.We thank Dr.Uwe Töpfer for valuable discussions and assistance in microscopy,Dennis Höfling for Hermetia breeding,and Katharina Starke,Yvonne Henker and Christin Froschauer for assistance in the laboratory.We thank the two anonymous reviewers for their helpful comments that improved the quality of the manuscript significantly.
文摘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.
基金supported by the grants of the National Natural Science Foundation of China(31970475 and 32170832 to YS,31970506 and 32170541 to LZ)the Fundamen-tal Research Funds for Central Universities,China(202012004 to LZ).
文摘Macrophages are well known for their phagocytic functions in innate immunity across species.In mammals,they rapidly consume a large amount of energy by shifting their metabolism from mitochondrial oxidative phosphorylation toward aerobic glycolysis,to perform the effective bactericidal function upon infection.Meanwhile,they strive for sufficient energy resources by restricting systemic metabolism.In contrast,under nutrient deprivation,the macrophage population is down-regulated to save energy for survival.Drosophila melanogaster possesses a highly conserved and comparatively simple innate immune system.Intriguingly,recent studies have shown that Drosophila plasmatocytes,the macrophage-like blood cells,adopt comparable metabolic remodeling and signaling pathways to achieve energy reassignment when challenged by pathogens,indicating the conservation of such metabolic strategies between insects and mammals.Here,focusing on Drosophila macrophages(plasmatocytes),we review recent advances regarding their comprehensive roles in local or systemic metabolism under homeostasis or stress,emphasizing macrophages as critical players in the crosstalk between the immune system and organic metabolism from a Drosophila perspective.
