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Hixson B, Huot L, Morejon B, Yang X, Nagy P, Michel K, Buchon N. The transcriptional response in mosquitoes distinguishes between fungi and bacteria but not Gram types. BMC Genomics 2024; 25:353. [PMID: 38594632 PMCID: PMC11003161 DOI: 10.1186/s12864-024-10153-0] [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: 10/31/2023] [Accepted: 02/22/2024] [Indexed: 04/11/2024] Open
Abstract
Mosquitoes are prolific vectors of human pathogens, therefore a clear and accurate understanding of the organization of their antimicrobial defenses is crucial for informing the development of transmission control strategies. The canonical infection response in insects, as described in the insect model Drosophila melanogaster, is pathogen type-dependent, with distinct stereotypical responses to Gram-negative bacteria and Gram-positive bacteria/fungi mediated by the activation of the Imd and Toll pathways, respectively. To determine whether this pathogen-specific discrimination is shared by mosquitoes, we used RNAseq to capture the genome-wide transcriptional response of Aedes aegypti and Anopheles gambiae (s.l.) to systemic infection with Gram-negative bacteria, Gram-positive bacteria, yeasts, and filamentous fungi, as well as challenge with heat-killed Gram-negative, Gram-positive, and fungal pathogens. From the resulting data, we found that Ae. aegypti and An. gambiae both mount a core response to all categories of infection, and this response is highly conserved between the two species with respect to both function and orthology. When we compared the transcriptomes of mosquitoes infected with different types of bacteria, we observed that the intensity of the transcriptional response was correlated with both the virulence and growth rate of the infecting pathogen. Exhaustive comparisons of the transcriptomes of Gram-negative-challenged versus Gram-positive-challenged mosquitoes yielded no difference in either species. In Ae. aegypti, however, we identified transcriptional signatures specific to bacterial infection and to fungal infection. The bacterial infection response was dominated by the expression of defensins and cecropins, while the fungal infection response included the disproportionate upregulation of an uncharacterized family of glycine-rich proteins. These signatures were also observed in Ae. aegypti challenged with heat-killed bacteria and fungi, indicating that this species can discriminate between molecular patterns that are specific to bacteria and to fungi.
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Affiliation(s)
- Bretta Hixson
- Cornell Institute of Host-Microbe Interactions and Disease, Department of Entomology, Cornell University, Ithaca, NY, 14853, USA
| | - Louise Huot
- Cornell Institute of Host-Microbe Interactions and Disease, Department of Entomology, Cornell University, Ithaca, NY, 14853, USA
| | - Bianca Morejon
- Division of Biology, Kansas State University, Manhattan, KS, 66506, USA
| | - Xiaowei Yang
- Cornell Institute of Host-Microbe Interactions and Disease, Department of Entomology, Cornell University, Ithaca, NY, 14853, USA
- Current address: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute for Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Peter Nagy
- Cornell Institute of Host-Microbe Interactions and Disease, Department of Entomology, Cornell University, Ithaca, NY, 14853, USA
| | - Kristin Michel
- Division of Biology, Kansas State University, Manhattan, KS, 66506, USA
| | - Nicolas Buchon
- Cornell Institute of Host-Microbe Interactions and Disease, Department of Entomology, Cornell University, Ithaca, NY, 14853, USA.
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Yang W, Lin Y, He Y, Li Q, Chen W, Lin Q, Swevers L, Liu J. BmPGPR-L4 is a negative regulator of the humoral immune response in the silkworm Bombyx mori. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2024; 115:e22093. [PMID: 38409870 DOI: 10.1002/arch.22093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 01/07/2024] [Accepted: 02/11/2024] [Indexed: 02/28/2024]
Abstract
Toll, immune deficiency and prophenoloxidase cascade represent vital immune signaling pathways in insects. Peptidoglycan recognition proteins (PGRPs) are innate immune receptors that activate and regulate the immune signaling pathways. Previously, we reported that BmPGPR-L4 was induced in the silkworm Bombyx mori larvae by bacteria and peptidoglycan challenges. Here, we focused on the function of BmPGRP-L4 in regulating the expression of antimicrobial peptides (AMPs). The hemolymph from BmPGRP-L4-silenced larvae exhibited an enhanced inhibitory effect on the growth of Escherichia coli, either by growth curve or inhibitory zone experiments. Coincidentally, most of the AMP genes were upregulated after RNAi of BmPGRP-L4. Oral administration of heat-inactivated E. coli and Staphylococcus aureus after RNAi of BmPGRP-L4 resulted in the increased expression of BmPGRP-L4 in different tissues of the silkworm larvae, revealing an auto-regulatory mechanism. By contrast, the expression of most AMP genes was downregulated by oral bacterial administration after RNAi of BmPGRP-L4. The above results demonstrate that BmPGRP-L4 recognizes bacterial pathogen-associated molecular patterns and negatively regulates AMP expression to achieve immunological homeostasis. As a negative regulator, BmPGPR-L4 is proposed to be involved in the feedback regulation of the immune signaling pathways of the silkworm to prevent excessive activation of the immune response.
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Affiliation(s)
- Weiyi Yang
- School of Life Sciences, Guangzhou University, Guangzhou, China
| | - Yongyi Lin
- School of Life Sciences, Guangzhou University, Guangzhou, China
| | - Yanying He
- School of Life Sciences, Guangzhou University, Guangzhou, China
| | - Qi Li
- School of Life Sciences, Guangzhou University, Guangzhou, China
| | - Weijian Chen
- School of Life Sciences, Guangzhou University, Guangzhou, China
| | - Qingsha Lin
- School of Life Sciences, Guangzhou University, Guangzhou, China
| | - Luc Swevers
- Institute of Biosciences and Applications, National Centre for Scientific Research Demokritos, Athens, Greece
| | - Jisheng Liu
- School of Life Sciences, Guangzhou University, Guangzhou, China
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Li Q, Zhang C, Zhang C, Duan R, Hua Y. CG4968 positively regulates the immune deficiency pathway by targeting Imd protein in Drosophila. PeerJ 2023; 11:e14870. [PMID: 36778143 PMCID: PMC9912943 DOI: 10.7717/peerj.14870] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 01/18/2023] [Indexed: 02/09/2023] Open
Abstract
Drosophila melanogaster relies solely on innate immunity to defend against various microbial pathogens. Although it is well-known that the adaptor protein Imd undergoes K63-linked ubiquitination to activate the downstream signaling cascades, its involvement with K48-linked ubiquitination and what is responsible for controlling this modification remain largely unknown. In this study, we explored the immunological function of CG4968, which encodes a typical ovarian tumour-associated protease (OTU)-type deubiquitinase (Dub) in flies. Our in vitro and vivo evidence demonstrated that CG4968 plays a positive role in governing the immune deficiency (IMD), but not the Toll innate immune response in an OTU domain-dependent manner. Mechanistically, we found that CG4968 is associated with Imd to restrict its K48-linked ubiquitination, thereby contributing to its turnover. Collectively, our study uncovered a novel regulatory mechanism involving the K48-linked ubiquitination of Imd in Drosophila innate immunity.
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Cammarata-Mouchtouris A, Acker A, Goto A, Chen D, Matt N, Leclerc V. Dynamic Regulation of NF-κB Response in Innate Immunity: The Case of the IMD Pathway in Drosophila. Biomedicines 2022; 10:biomedicines10092304. [PMID: 36140409 PMCID: PMC9496462 DOI: 10.3390/biomedicines10092304] [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: 07/31/2022] [Revised: 09/01/2022] [Accepted: 09/08/2022] [Indexed: 11/16/2022] Open
Abstract
Metazoans have developed strategies to protect themselves from pathogenic attack. These preserved mechanisms constitute the immune system, composed of innate and adaptive responses. Among the two kinds, the innate immune system involves the activation of a fast response. NF-κB signaling pathways are activated during infections and lead to the expression of timely-controlled immune response genes. However, activation of NF-κB pathways can be deleterious when uncontrolled. Their regulation is necessary to prevent the development of inflammatory diseases or cancers. The similarity of the NF-κB pathways mediating immune mechanisms in insects and mammals makes Drosophila melanogaster a suitable model for studying the innate immune response and learning general mechanisms that are also relevant for humans. In this review, we summarize what is known about the dynamic regulation of the central NF-κB-pathways and go into detail on the molecular level of the IMD pathway. We report on the role of the nuclear protein Akirin in the regulation of the NF-κB Relish immune response. The use of the Drosophila model allows the understanding of the fine-tuned regulation of this central NF-κB pathway.
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Affiliation(s)
| | - Adrian Acker
- Institut de Biologie Moléculaire et Cellulaire (IBMC), UPR9022, CNRS, Université de Strasbourg, 67084 Strasbourg, France
| | - Akira Goto
- Institut de Biologie Moléculaire et Cellulaire (IBMC), UPR9022, CNRS, Université de Strasbourg, 67084 Strasbourg, France
| | - Di Chen
- Sino-French Hoffmann Institute, School of Basic Medical Science, Guangzhou Medical University, Guangzhou 511436, China
| | - Nicolas Matt
- Institut de Biologie Moléculaire et Cellulaire (IBMC), UPR9022, CNRS, Université de Strasbourg, 67084 Strasbourg, France
- Correspondence: (N.M.); (V.L.)
| | - Vincent Leclerc
- Institut de Biologie Moléculaire et Cellulaire (IBMC), UPR9022, CNRS, Université de Strasbourg, 67084 Strasbourg, France
- Correspondence: (N.M.); (V.L.)
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