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Peng Z, Zhang W, Fu H, Li Y, Zhang C, Li J, Chan J, Zhang L. Genome-Wide Comparative Analysis of SRCR Gene Superfamily in Invertebrates Reveals Massive and Independent Gene Expansions in the Sponge and Sea Urchin. Int J Mol Sci 2024; 25:1515. [PMID: 38338794 PMCID: PMC10855680 DOI: 10.3390/ijms25031515] [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: 11/17/2023] [Revised: 01/12/2024] [Accepted: 01/22/2024] [Indexed: 02/12/2024] Open
Abstract
Without general adaptative immunity, invertebrates evolved a vast number of heterogeneous non-self recognition strategies. One of those well-known adaptations is the expansion of the immune receptor gene superfamily coding for scavenger receptor cysteine-rich domain containing proteins (SRCR) in a few invertebrates. Here, we investigated the evolutionary history of the SRCR gene superfamily (SRCR-SF) across 29 metazoan species with an emphasis on invertebrates. We analyzed their domain architectures, genome locations and phylogenetic distribution. Our analysis shows extensive genome-wide duplications of the SRCR-SFs in Amphimedon queenslandica and Strongylocentrotus purpuratus. Further molecular evolution study reveals various patterns of conserved cysteines in the sponge and sea urchin SRCR-SFs, indicating independent and convergent evolution of SRCR-SF expansion during invertebrate evolution. In the case of the sponge SRCR-SFs, a novel motif with seven conserved cysteines was identified. Exon-intron structure analysis suggests the rapid evolution of SRCR-SFs during gene duplications in both the sponge and the sea urchin. Our findings across nine representative metazoans also underscore a heightened expression of SRCR-SFs in immune-related tissues, notably the digestive glands. This observation indicates the potential role of SRCR-SFs in reinforcing distinct immune functions in these invertebrates. Collectively, our results reveal that gene duplication, motif structure variation, and exon-intron divergence might lead to the convergent evolution of SRCR-SF expansions in the genomes of the sponge and sea urchin. Our study also suggests that the utilization of SRCR-SF receptor duplication may be a general and basal strategy to increase immune diversity and tissue specificity for the invertebrates.
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Affiliation(s)
- Zhangjie Peng
- College of Life Sciences, School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao 266109, China; (Z.P.); (H.F.); (Y.L.); (C.Z.)
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center of Deep-Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
- College of Marine Science, University of Chinese Academy of Sciences, Beijing 100049, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
| | - Wei Zhang
- College of Life Sciences, School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao 266109, China; (Z.P.); (H.F.); (Y.L.); (C.Z.)
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center of Deep-Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| | - Hailun Fu
- College of Life Sciences, School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao 266109, China; (Z.P.); (H.F.); (Y.L.); (C.Z.)
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center of Deep-Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| | - Yuzhu Li
- College of Life Sciences, School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao 266109, China; (Z.P.); (H.F.); (Y.L.); (C.Z.)
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center of Deep-Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| | - Chunyu Zhang
- College of Life Sciences, School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao 266109, China; (Z.P.); (H.F.); (Y.L.); (C.Z.)
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center of Deep-Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| | - Jie Li
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center of Deep-Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
- College of Marine Science, University of Chinese Academy of Sciences, Beijing 100049, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Chinese Academy of Sciences, Qingdao 266071, China
| | - Jiulin Chan
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center of Deep-Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Chinese Academy of Sciences, Qingdao 266071, China
| | - Linlin Zhang
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center of Deep-Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
- College of Marine Science, University of Chinese Academy of Sciences, Beijing 100049, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Chinese Academy of Sciences, Qingdao 266071, China
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Khan SA, Kojour MAM, Han YS. Recent trends in insect gut immunity. Front Immunol 2023; 14:1272143. [PMID: 38193088 PMCID: PMC10773798 DOI: 10.3389/fimmu.2023.1272143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 11/29/2023] [Indexed: 01/10/2024] Open
Abstract
The gut is a crucial organ in insect defense against various pathogens and harmful substances in their environment and diet. Distinct insect gut compartments possess unique functionalities contributing to their physiological processes, including immunity. The insect gut's cellular composition is vital for cellular and humoral immunity. The peritrophic membrane, mucus layer, lumen, microvilli, and various gut cells provide essential support for activating and regulating immune defense mechanisms. These components also secrete molecules and enzymes that are imperative in physiological activities. Additionally, the gut microbiota initiates various signaling pathways and produces vitamins and minerals that help maintain gut homeostasis. Distinct immune signaling pathways are activated within the gut when insects ingest pathogens or hazardous materials. The pathway induced depends on the infection or pathogen type; include immune deficiency (imd), Toll, JAK/STAT, Duox-ROS, and JNK/FOXO regulatory pathways. These pathways produce different antimicrobial peptides (AMPs) and maintain gut homeostasis. Furthermore, various signaling mechanisms within gut cells regulate insect gut recovery following infection. Although some questions regarding insect gut immunity in different species require additional study, this review provides insights into the insect gut's structure and composition, commensal microorganism roles in Drosophila melanogaster and Tenebrio molitor life cycles, different signaling pathways involved in gut immune systems, and the insect gut post-infection recovery through various signaling mechanisms.
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Affiliation(s)
- Shahidul Ahmed Khan
- Department of Applied Biology, Institute of Environmentally Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju, Republic of Korea
| | - Maryam Ali Mohmmadie Kojour
- Life & Medical Sciences Institute (LIMES) Development, Genetics & Molecular Physiology Unit, University of Bonn, Bonn, Germany
| | - Yeon Soo Han
- Department of Applied Biology, Institute of Environmentally Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju, Republic of Korea
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3
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Aalto AL, Luukkonen V, Meinander A. Ubiquitin signalling in Drosophila innate immune responses. FEBS J 2023. [PMID: 38069549 DOI: 10.1111/febs.17028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/24/2023] [Accepted: 12/07/2023] [Indexed: 12/19/2023]
Abstract
Cells respond to invading pathogens and danger signals from the environment by adapting gene expression to meet the need for protective effector molecules. While this innate immune response is required for the cell and the organism to recover, excess immune activation may lead to loss of homeostasis, thereby promoting chronic inflammation and cancer progression. The molecular basis of innate immune defence is comprised of factors promoting survival and proliferation, such as cytokines, antimicrobial peptides and anti-apoptotic proteins. As the molecular mechanisms regulating innate immune responses are conserved through evolution, the fruit fly Drosophila melanogaster serves as a convenient, affordable and ethical model organism to enhance understanding of immune signalling. Fly immunity against bacterial infection is built up by both cellular and humoral responses, where the latter is regulated by the Imd and Toll pathways activating NF-κB transcription factors Relish, Dorsal and Dif, as well as JNK activation and JAK/STAT signalling. As in mammals, the Drosophila innate immune signalling pathways are characterised by ubiquitination of signalling molecules followed by ubiquitin receptors binding to the ubiquitin chains, as well as by rapid changes in protein levels by ubiquitin-mediated targeted proteasomal and lysosomal degradation. In this review, we summarise the molecular signalling pathways regulating immune responses to pathogen infection in Drosophila, with a focus on ubiquitin-dependent control of innate immunity and inflammatory signalling.
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Affiliation(s)
- Anna L Aalto
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, Turku, Finland
- InFLAMES Research Flagship, Åbo Akademi University, Turku, Finland
| | - Veera Luukkonen
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, Turku, Finland
| | - Annika Meinander
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, Turku, Finland
- InFLAMES Research Flagship, Åbo Akademi University, Turku, Finland
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Zang Y, Bashaw GJ. Systematic analysis of the Frazzled receptor interactome establishes previously unreported regulators of axon guidance. Development 2023; 150:dev201636. [PMID: 37526651 PMCID: PMC10445734 DOI: 10.1242/dev.201636] [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: 01/19/2023] [Accepted: 07/07/2023] [Indexed: 08/02/2023]
Abstract
The Netrin receptor Dcc and its Drosophila homolog Frazzled play crucial roles in diverse developmental process, including axon guidance. In Drosophila, Fra regulates midline axon guidance through a Netrin-dependent and a Netrin-independent pathway. However, what molecules regulate these distinct signaling pathways remain unclear. To identify Fra-interacting proteins, we performed affinity purification mass spectrometry to establish a neuronal-specific Fra interactome. In addition to known interactors of Fra and Dcc, including Netrin and Robo1, our screen identified 85 candidate proteins, the majority of which are conserved in humans. Many of these proteins are expressed in the ventral nerve cord, and gene ontology, pathway analysis and biochemical validation identified several previously unreported pathways, including the receptor tyrosine phosphatase Lar, subunits of the COP9 signalosome and Rho-5, a regulator of the metalloprotease Tace. Finally, genetic analysis demonstrates that these genes regulate axon guidance and may define as yet unknown signaling mechanisms for Fra and its vertebrate homolog Dcc. Thus, the Fra interactome represents a resource to guide future functional studies.
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Affiliation(s)
- Yixin Zang
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, 415 Curie Blvd, Philadelphia, PA, 19104, USA
| | - Greg J. Bashaw
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, 415 Curie Blvd, Philadelphia, PA, 19104, USA
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Kuebler CA, Paré AC. Striped Expression of Leucine-Rich Repeat Proteins Coordinates Cell Intercalation and Compartment Boundary Formation in the Early Drosophila Embryo. Symmetry (Basel) 2023; 15:1490. [PMID: 38650964 PMCID: PMC11034934 DOI: 10.3390/sym15081490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024] Open
Abstract
Planar polarity is a commonly observed phenomenon in which proteins display a consistent asymmetry in their subcellular localization or activity across the plane of a tissue. During animal development, planar polarity is a fundamental mechanism for coordinating the behaviors of groups of cells to achieve anisotropic tissue remodeling, growth, and organization. Therefore, a primary focus of developmental biology research has been to understand the molecular mechanisms underlying planar polarity in a variety of systems to identify conserved principles of tissue organization. In the early Drosophila embryo, the germband neuroectoderm epithelium rapidly doubles in length along the anterior-posterior axis through a process known as convergent extension (CE); it also becomes subdivided into tandem tissue compartments through the formation of compartment boundaries (CBs). Both processes are dependent on the planar polarity of proteins involved in cellular tension and adhesion. The enrichment of actomyosin-based tension and adherens junction-based adhesion at specific cell-cell contacts is required for coordinated cell intercalation, which drives CE, and the creation of highly stable cell-cell contacts at CBs. Recent studies have revealed a system for rapid cellular polarization triggered by the expression of leucine-rich-repeat (LRR) cell-surface proteins in striped patterns. In particular, the non-uniform expression of Toll-2, Toll-6, Toll-8, and Tartan generates local cellular asymmetries that allow cells to distinguish between cell-cell contacts oriented parallel or perpendicular to the anterior-posterior axis. In this review, we discuss (1) the biomechanical underpinnings of CE and CB formation, (2) how the initial symmetry-breaking events of anterior-posterior patterning culminate in planar polarity, and (3) recent advances in understanding the molecular mechanisms downstream of LRR receptors that lead to planar polarized tension and junctional adhesion.
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Affiliation(s)
- Chloe A. Kuebler
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701, USA
| | - Adam C. Paré
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR 72701, USA
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Ali Mohammadie Kojour M, Jang HA, Lee YS, Jo YH, Han YS. Innate Immune Response of TmToll-3 Following Systemic Microbial Infection in Tenebrio molitor. Int J Mol Sci 2023; 24:ijms24076751. [PMID: 37047723 PMCID: PMC10095136 DOI: 10.3390/ijms24076751] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 03/28/2023] [Accepted: 03/29/2023] [Indexed: 04/08/2023] Open
Abstract
Although Toll-like receptors have been widely identified and functionally characterized in mammalian models and Drosophila, the immunological function of these receptors in other insects remains unclear. Here, we explored the relevant innate immune response of Tenebrio molitor (T. molitor) Toll-3 against Gram-negative bacteria, Gram-positive bacteria, and fungal infections. Our findings indicated that TmToll-3 expression was mainly induced by Candida albicans infections in the fat bodies, gut, Malpighian tubules, and hemolymph of young T. molitor larvae. Surprisingly, Escherichia coli systemic infection caused mortality after TmToll-3 knockdown via RNA interference (RNAi) injection, which was not observed in the control group. Further analyses indicated that in the absence of TmToll-3, the final effector of the Toll signaling pathway, antimicrobial peptide (AMP) genes and relevant transcription factors were significantly downregulated after E. coli challenge. Our results indicated that the expression of almost all AMP genes was suppressed in silenced individuals, whereas the expression of relevant genes was positively regulated after fungal injection. Therefore, this study revealed the immunological involvement of TmToll-3 in T. molitor in response to systematic infections.
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Affiliation(s)
- Maryam Ali Mohammadie Kojour
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Ho Am Jang
- Department of Biology, College of Natural Sciences, Soonchunhyang University, Asan 31538, Republic of Korea
| | - Yong Seok Lee
- Department of Biology, College of Natural Sciences, Soonchunhyang University, Asan 31538, Republic of Korea
| | - Yong Hun Jo
- Department of Biology, College of Natural Sciences, Soonchunhyang University, Asan 31538, Republic of Korea
| | - Yeon Soo Han
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Republic of Korea
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7
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Ali Mohammadie Kojour M, Jang HA, Lee YS, Jo YH, Han YS. Immunological Roles of TmToll-2 in Response to Escherichia coli Systemic Infection in Tenebrio molitor. Int J Mol Sci 2022; 23:ijms232214490. [PMID: 36430968 PMCID: PMC9699188 DOI: 10.3390/ijms232214490] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/14/2022] [Accepted: 11/17/2022] [Indexed: 11/23/2022] Open
Abstract
The antimicrobial roles of Toll-like receptors have been mainly identified in mammalian models and Drosophila. However, its immunological function in other insects has yet to be fully clarified. Here, we determined the innate immune response involvement of TmToll-2 encountering Gram-negative, Gram-positive, and fungal infection. Our data revealed that TmToll-2 expression could be induced by Escherichia coli, Staphylococcus aureus, and Candida albicans infections in the fat bodies, gut, Malpighian tubules, and hemolymph of Tenebrio molitor young larvae. However, TmToll-2 silencing via RNAi technology revealed that sole E. coli systemic infection caused mortality in the double-strand RNA TmToll-2-injected group compared with that in the control group. Further investigation indicated that in the absence of TmToll-2, the final effector of Toll signaling pathway, antimicrobial peptide (AMP) genes and relevant transcription factors were significantly downregulated, mainly E. coli post-insult. We showed that the expression of all AMP genes was suppressed in the main immune organ of insects, namely, fat bodies, in silenced individuals, while the relevant expressions were not affected after fungal infection. Thus, our research revealed the immunological roles of TmToll-2 in different organs of T. molitor in response to pathogenic insults.
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Affiliation(s)
- Maryam Ali Mohammadie Kojour
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Ho Am Jang
- Department of Biology, College of Natural Sciences, Soonchunhyang University, Asan 31538, Republic of Korea
| | - Yong Seok Lee
- Department of Biology, College of Natural Sciences, Soonchunhyang University, Asan 31538, Republic of Korea
| | - Yong Hun Jo
- Department of Biology, College of Natural Sciences, Soonchunhyang University, Asan 31538, Republic of Korea
- Correspondence: (Y.H.J.); (Y.S.H.)
| | - Yeon Soo Han
- Department of Applied Biology, Institute of Environmentally-Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Republic of Korea
- Correspondence: (Y.H.J.); (Y.S.H.)
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Umetsu D. Cell mechanics and cell-cell recognition controls by Toll-like receptors in tissue morphogenesis and homeostasis. Fly (Austin) 2022; 16:233-247. [PMID: 35579305 PMCID: PMC9116419 DOI: 10.1080/19336934.2022.2074783] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Signal transduction by the Toll-like receptors (TLRs) is conserved and essential for innate immunity in metazoans. The founding member of the TLR family, Drosophila Toll-1, was initially identified for its role in dorsoventral axis formation in early embryogenesis. The Drosophila genome encodes nine TLRs that display dynamic expression patterns during development, suggesting their involvement in tissue morphogenesis and homeostasis. Recent progress on the developmental functions of TLRs beyond dorsoventral patterning has revealed not only their diverse functions in various biological processes, but also unprecedented molecular mechanisms in directly regulating cell mechanics and cell-cell recognition independent of the canonical signal transduction pathway involving transcriptional regulation of target genes. In this review, I feature and discuss the non-immune functions of TLRs in the control of epithelial tissue homeostasis, tissue morphogenesis, and cell-cell recognition between cell populations with different cell identities.
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Affiliation(s)
- Daiki Umetsu
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan
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9
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Meng F, Han H, Wang M, Jiang Y, Pi Z, Qu Y, Liu Z, Cai J. Characterized Gene Repertoires and Functional Gene Reference for Forensic Entomology: Genomic and Developmental Transcriptomic Analysis of Aldrichina grahami (Diptera: Calliphoridae). JOURNAL OF MEDICAL ENTOMOLOGY 2022; 59:810-819. [PMID: 35139213 DOI: 10.1093/jme/tjac004] [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: 03/17/2021] [Indexed: 06/14/2023]
Abstract
Many flies of Diptera are common entomological evidence employed in forensic investigation. Exploring the existence of inter- and intra-species genomic differences of forensically relevant insects is of great importance. Aldrichina grahami is a common blow fly species of forensic importance. The present study characterized the gene repertoires of A. grahami, and provides insights into issues related to forensic entomology, such as necrophagous behavior, gene family features, and developmental patterns. Gene families were clustered and classified according to their function in different aspects of the necrophagous lifestyle, generating several gene repertoires. The genes under positive selection pressure and evolutionary changes were screen and identified. Moreover, genes that exhibited potential prediction value in the post mortem interval (PMI) estimation and development of immature stages were subjected to analysis based on the developmental transcriptome. Related insect species were compared at the genomic level to reveal the genes associated with necrophagous behaviors. The expression of selected genes in separated repositories was verified using qPCR. This work was conducted using a high-quality chromosome-level genome assembly of A. grahami and its developmental transcriptome. The findings will facilitate future research on A. grahami and the other forensically important species.
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Affiliation(s)
- Fanming Meng
- School of Basic Medicine, Central South University, Changsha, China
| | - Han Han
- School of Basic Medicine, Central South University, Changsha, China
| | - Mo Wang
- Key Laboratory for Conserving Wildlife with Small Populations in Yunnan, Faculty of Biodiversity Conservation, Southwest Forestry University, Kunming, China
| | - Yangshuai Jiang
- School of Basic Medicine, Central South University, Changsha, China
| | - Zhiyun Pi
- School of Basic Medicine, Central South University, Changsha, China
| | - Yihong Qu
- School of Basic Medicine, Central South University, Changsha, China
| | - Zhuoying Liu
- School of Basic Medicine, Central South University, Changsha, China
| | - Jifeng Cai
- School of Basic Medicine, Central South University, Changsha, China
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10
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Cheung YP, Park S, Pagtalunan J, Maringer K. The antiviral role of NF-κB-mediated immune responses and their antagonism by viruses in insects. J Gen Virol 2022; 103. [PMID: 35510990 DOI: 10.1099/jgv.0.001741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The antiviral role of innate immune responses mediated by the NF-κB family of transcription factors is well established in vertebrates but was for a long time less clear in insects. Insects encode two canonical NF-κB pathways, the Toll and Imd ('immunodeficiency') pathways, which are best characterised for their role in antibacterial and antifungal defence. An increasing body of evidence has also implicated NF-κB-mediated innate immunity in antiviral responses against some, but not all, viruses. Specific pattern recognition receptors (PRRs) and molecular events leading to NF-κB activation by viral pathogen-associated molecular patterns (PAMPs) have been elucidated for a number of viruses and insect species. Particularly interesting are recent findings indicating that the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway detects viral RNA to activate NF-κB-regulated gene expression. We summarise the literature on virus-NF-κB pathway interactions across the class Insecta, with a focus on the dipterans Drosophila melanogaster and Aedes aegypti. We discuss potential reasons for differences observed between different virus-host combinations, and highlight similarities and differences between cGAS-STING signalling in insects versus vertebrates. Finally, we summarise the increasing number of known molecular mechanisms by which viruses antagonise NF-κB responses, which suggest that NF-κB-mediated immunity exerts strong evolutionary pressures on viruses. These developments in our understanding of insect antiviral immunity have relevance to the large number of insect species that impact on humans through their transmission of human, livestock and plant diseases, exploitation as biotechnology platforms, and role as parasites, pollinators, livestock and pests.
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Affiliation(s)
- Yin P Cheung
- The Pirbright Institute, Pirbright, Surrey, GU24 0NF, UK.,Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, GU2 7XH, UK
| | - Sohyun Park
- The Pirbright Institute, Pirbright, Surrey, GU24 0NF, UK.,Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, GU2 7XH, UK
| | - Justine Pagtalunan
- The Pirbright Institute, Pirbright, Surrey, GU24 0NF, UK.,Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, GU2 7XH, UK
| | - Kevin Maringer
- The Pirbright Institute, Pirbright, Surrey, GU24 0NF, UK
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Divergences of the RLR Gene Families across Lophotrochozoans: Domain Grafting, Exon-Intron Structure, Expression, and Positive Selection. Int J Mol Sci 2022; 23:ijms23073415. [PMID: 35408776 PMCID: PMC8998645 DOI: 10.3390/ijms23073415] [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] [Received: 01/29/2022] [Revised: 03/06/2022] [Accepted: 03/10/2022] [Indexed: 02/04/2023] Open
Abstract
Invertebrates do not possess adaptive immunity but have evolved a variety of unique repertoires of innate immune sensors. In this study, we explored the immune diversity and specificity of invertebrates based on the lophotrochozoan RLRs, a major component in antiviral immune recognition. By annotating RLRs in the genomes of 58 representative species across metazoan evolution, we explored the gene expansion of RLRs in Lophotrochozoa. Of note, the N-terminal domains of lophotrochozoan RLRs showed the most striking diversity which evolved independently by domain grafting. Exon–intron structures were revealed to be prevalent in the domain grafting of lophotrochozoan RLRs based on an analysis of sibling paralogs and orthologs. In more than half of the cases, the mechanism of ‘exonization/pseudoexonization’ led to the generation of non-canonical N-terminal domains. Transcriptomic studies revealed that many non-canonical RLRs display immune-related expression patterns. Two of these RLRs showed obvious evidence of positive selection, which may be the result of host defense selection pressure. Overall, our study suggests that the complex and unique domain arrangement of lophotrochozoan RLRs might result from domain grafting, exon–intron divergence, expression diversification, and positive selection, which may have led to functionally distinct lophotrochozoan RLRs.
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Lima LF, Torres AQ, Jardim R, Mesquita RD, Schama R. Evolution of Toll, Spatzle and MyD88 in insects: the problem of the Diptera bias. BMC Genomics 2021; 22:562. [PMID: 34289811 PMCID: PMC8296651 DOI: 10.1186/s12864-021-07886-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 07/13/2021] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Arthropoda, the most numerous and diverse metazoan phylum, has species in many habitats where they encounter various microorganisms and, as a result, mechanisms for pathogen recognition and elimination have evolved. The Toll pathway, involved in the innate immune system, was first described as part of the developmental pathway for dorsal-ventral differentiation in Drosophila. Its later discovery in vertebrates suggested that this system was extremely conserved. However, there is variation in presence/absence, copy number and sequence divergence in various genes along the pathway. As most studies have only focused on Diptera, for a comprehensive and accurate homology-based approach it is important to understand gene function in a number of different species and, in a group as diverse as insects, the use of species belonging to different taxonomic groups is essential. RESULTS We evaluated the diversity of Toll pathway gene families in 39 Arthropod genomes, encompassing 13 different Insect Orders. Through computational methods, we shed some light into the evolution and functional annotation of protein families involved in the Toll pathway innate immune response. Our data indicates that: 1) intracellular proteins of the Toll pathway show mostly species-specific expansions; 2) the different Toll subfamilies seem to have distinct evolutionary backgrounds; 3) patterns of gene expansion observed in the Toll phylogenetic tree indicate that homology based methods of functional inference might not be accurate for some subfamilies; 4) Spatzle subfamilies are highly divergent and also pose a problem for homology based inference; 5) Spatzle subfamilies should not be analyzed together in the same phylogenetic framework; 6) network analyses seem to be a good first step in inferring functional groups in these cases. We specifically show that understanding Drosophila's Toll functions might not indicate the same function in other species. CONCLUSIONS Our results show the importance of using species representing the different orders to better understand insect gene content, origin and evolution. More specifically, in intracellular Toll pathway gene families the presence of orthologues has important implications for homology based functional inference. Also, the different evolutionary backgrounds of Toll gene subfamilies should be taken into consideration when functional studies are performed, especially for TOLL9, TOLL, TOLL2_7, and the new TOLL10 clade. The presence of Diptera specific clades or the ones lacking Diptera species show the importance of overcoming the Diptera bias when performing functional characterization of Toll pathways.
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Affiliation(s)
- Letícia Ferreira Lima
- Laboratório de Biologia Computacional e Sistemas, Oswaldo Cruz Foundation, Fiocruz, Rio de Janeiro, Brazil
| | - André Quintanilha Torres
- Laboratório de Biologia Computacional e Sistemas, Oswaldo Cruz Foundation, Fiocruz, Rio de Janeiro, Brazil
| | - Rodrigo Jardim
- Laboratório de Biologia Computacional e Sistemas, Oswaldo Cruz Foundation, Fiocruz, Rio de Janeiro, Brazil
| | - Rafael Dias Mesquita
- Laboratório de Bioinformática, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular-INCT-EM, Rio de Janeiro, Brazil
| | - Renata Schama
- Laboratório de Biologia Computacional e Sistemas, Oswaldo Cruz Foundation, Fiocruz, Rio de Janeiro, Brazil.
- Instituto Nacional de Ciência e Tecnologia em Entomologia Molecular-INCT-EM, Rio de Janeiro, Brazil.
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13
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Kong D, Großhans J. Planar Cell Polarity and E-Cadherin in Tissue-Scale Shape Changes in Drosophila Embryos. Front Cell Dev Biol 2020; 8:619958. [PMID: 33425927 PMCID: PMC7785826 DOI: 10.3389/fcell.2020.619958] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 12/07/2020] [Indexed: 12/04/2022] Open
Abstract
Planar cell polarity and anisotropic cell behavior play critical roles in large-scale epithelial morphogenesis, homeostasis, wound repair, and regeneration. Cell-Cell communication and mechano-transduction in the second to minute scale mediated by E-cadherin complexes play a central role in the coordination and self-organization of cellular activities, such as junction dynamics, cell shape changes, and cell rearrangement. Here we review the current understanding in the interplay of cell polarity and cell dynamics during body axis elongation and dorsal closure in Drosophila embryos with a focus on E-cadherin dynamics in linking cell and tissue polarization and tissue-scale shape changes.
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Affiliation(s)
- Deqing Kong
- Department of Biology, Philipps-University Marburg, Marburg, Germany
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14
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Abstract
Convergent extension is a conserved mechanism for elongating tissues. In the Drosophila embryo, convergent extension is driven by planar polarized cell intercalation and is a paradigm for understanding the cellular, molecular, and biophysical mechanisms that establish tissue structure. Studies of convergent extension in Drosophila have provided key insights into the force-generating molecules that promote convergent extension in epithelial tissues, as well as the global systems of spatial information that systematically organize these cell behaviors. A general framework has emerged in which asymmetrically localized proteins involved in cytoskeletal tension and cell adhesion direct oriented cell movements, and spatial signals provided by the Toll, Tartan, and Teneurin receptor families break planar symmetry to establish and coordinate planar cell polarity throughout the tissue. In this chapter, we describe the cellular, molecular, and biophysical mechanisms that regulate cell intercalation in the Drosophila embryo, and discuss how research in this system has revealed conserved biological principles that control the organization of multicellular tissues and animal body plans.
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Affiliation(s)
- Adam C Paré
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, United States.
| | - Jennifer A Zallen
- Howard Hughes Medical Institute and Developmental Biology Program, Sloan Kettering Institute, New York, NY, United States.
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15
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Graham PL, Anderson WR, Brandt EA, Xiang J, Pick L. Dynamic expression of Drosophila segmental cell surface-encoding genes and their pair-rule regulators. Dev Biol 2019; 447:147-156. [PMID: 30695684 DOI: 10.1016/j.ydbio.2019.01.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/10/2019] [Accepted: 01/19/2019] [Indexed: 11/28/2022]
Abstract
Drosophila segmentation is regulated by a complex network of transcription factors that include products of the pair-rule genes (PRGs). PRGs are expressed in early embryos in the primorida of alternate segmental units, establishing the repeated, segmental body plan of the fly. Despite detailed analysis of the regulatory logic among segmentation genes, the relationship between these genes and the morphological formation of segments is still poorly understood, since regulation of transcription factor expression is not sufficient to explain how segments actually form and are maintained. Cell surface proteins containing Leucine rich repeats (LRR) play a variety of roles in development, and those expressed in segmental patterns likely impact segment morphogenesis. Here we explore the relationships between the PRG network and segmentally expressed LRR-encoding (sLRR) genes. We examined expression of Toll2, Toll6, Toll7, Toll8 and tartan (trn) in wild type or PRG mutant embryos. Expression of each sLRR-encoding gene is dynamic, but each has a unique register along the anterior-posterior axis. The registers for different sLRRs are off-set from one another resulting in a continually changing set of overlapping expression patterns among the sLRR-encoding genes themselves and between the sLRR-encoding genes and the PRGs. Accordingly, each sLRR-encoding gene is regulated by a unique combination of PRGs. These findings suggest that one role of the PRG network is to promote segmentation by establishing a cell surface code: each row of cells in the two-segment-wide primordia expresses a unique combination of sLRRs, thereby translating regulatory information from the PRGs to direct segment morphogenesis.
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Affiliation(s)
- Patricia L Graham
- Entomology Department, University of Maryland, College Park, MD 20742, United States
| | - W Ray Anderson
- Entomology Department, University of Maryland, College Park, MD 20742, United States
| | - Elizabeth A Brandt
- Entomology Department, University of Maryland, College Park, MD 20742, United States
| | - Jie Xiang
- Entomology Department, University of Maryland, College Park, MD 20742, United States
| | - Leslie Pick
- Entomology Department, University of Maryland, College Park, MD 20742, United States.
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16
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Janssen R, Lionel L. Embryonic expression of a Long Toll (Loto) gene in the onychophorans Euperipatoides kanangrensis and Cephalofovea clandestina. Dev Genes Evol 2018; 228:171-178. [PMID: 29802495 PMCID: PMC6013529 DOI: 10.1007/s00427-018-0609-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 03/27/2018] [Indexed: 11/25/2022]
Abstract
Recent research has shown that Toll genes, and in particular a newly defined class of Toll genes, the so-called Long Toll Genes (Loto genes), are crucial factors in embryogenesis. In arthropods, they are involved in axis formation via a process called convergent extension (CE). A hallmark of Loto genes is their relatively (compared to other Toll genes) high number of leucine-rich repeat elements (LRRs) coupled with the fact that they are expressed in transverse stripes in all segments, or a subset of segments, patterns that are reminiscent of classical segmentation genes such as the pair-rule genes. Onychophorans represent a close outgroup to the arthropods; however, their embryonic development differs substantially. It is unclear if convergent extension contributes to onychophoran germ band formation and, if so, whether Loto genes are involved in governing this process. This study identifies a single onychophoran Toll gene from a sequenced embryonic transcriptome in two onychophoran species. The identified gene shows sequence and expression pattern characteristics of Loto genes. However, its expression pattern also comprises some general differences to arthropod Loto genes that are involved in CE.
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Affiliation(s)
- Ralf Janssen
- Department of Earth Sciences, Palaeobiology, Uppsala University, Villavägen 16, 75236, Uppsala, Sweden.
| | - Linushiya Lionel
- Department of Earth Sciences, Palaeobiology, Uppsala University, Villavägen 16, 75236, Uppsala, Sweden
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17
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Gerdol M, Luo YJ, Satoh N, Pallavicini A. Genetic and molecular basis of the immune system in the brachiopod Lingula anatina. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2018; 82:7-30. [PMID: 29278680 DOI: 10.1016/j.dci.2017.12.021] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 12/20/2017] [Accepted: 12/21/2017] [Indexed: 06/07/2023]
Abstract
The extension of comparative immunology to non-model systems, such as mollusks and annelids, has revealed an unexpected diversity in the complement of immune receptors and effectors among evolutionary lineages. However, several lophotrochozoan phyla remain unexplored mainly due to the lack of genomic resources. The increasing accessibility of high-throughput sequencing technologies offers unique opportunities for extending genome-wide studies to non-model systems. As a result, the genome-based study of the immune system in brachiopods allows a better understanding of the alternative survival strategies developed by these immunologically neglected phyla. Here we present a detailed overview of the molecular components of the immune system identified in the genome of the brachiopod Lingula anatina. Our findings reveal conserved intracellular signaling pathways as well as unique strategies for pathogen detection and killing in brachiopods.
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Affiliation(s)
- Marco Gerdol
- Department of Life Sciences, University of Trieste, Via Giorgieri 5, 34127 Trieste, Italy.
| | - Yi-Jyun Luo
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0495, Japan
| | - Noriyuki Satoh
- Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0495, Japan
| | - Alberto Pallavicini
- Department of Life Sciences, University of Trieste, Via Giorgieri 5, 34127 Trieste, Italy; Anton Dohrn Zoological Station, Villa Comunale, 80121 Napoli, Italy
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18
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Levin TC, Malik HS. Rapidly Evolving Toll-3/4 Genes Encode Male-Specific Toll-Like Receptors in Drosophila. Mol Biol Evol 2017; 34:2307-2323. [PMID: 28541576 PMCID: PMC5850136 DOI: 10.1093/molbev/msx168] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Animal Toll-like receptors (TLRs) have evolved through a pattern of duplication and divergence. Whereas mammalian TLRs directly recognize microbial ligands, Drosophila Tolls bind endogenous ligands downstream of both developmental and immune signaling cascades. Here, we find that most Toll genes in Drosophila evolve slowly with little gene turnover (gains/losses), consistent with their important roles in development and indirect roles in microbial recognition. In contrast, we find that the Toll-3/4 genes have experienced an unusually rapid rate of gene gains and losses, resulting in lineage-specific Toll-3/4s and vastly different gene repertoires among Drosophila species, from zero copies (e.g., D. mojavensis) to nineteen copies (e.g., D. willistoni). In D. willistoni, we find strong evidence for positive selection in Toll-3/4 genes, localized specifically to an extracellular region predicted to overlap with the binding site of Spätzle, the only known ligand of insect Tolls. However, because Spätzle genes are not experiencing similar selective pressures, we hypothesize that Toll-3/4s may be rapidly evolving because they bind to a different ligand, akin to TLRs outside of insects. We further find that most Drosophila Toll-3/4 genes are either weakly expressed or expressed exclusively in males, specifically in the germline. Unlike other Toll genes in D. melanogaster, Toll-3, and Toll-4 have apparently escaped from essential developmental roles, as knockdowns have no substantial effects on viability or male fertility. Based on these findings, we propose that the Toll-3/4 genes represent an exceptionally rapidly evolving lineage of Drosophila Toll genes, which play an unusual, as-yet-undiscovered role in the male germline.
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Affiliation(s)
- Tera C Levin
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Harmit S Malik
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA.,Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, WA
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19
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Zhang C, Yan SQ, Shen BB, Ali S, Wang XM, Jin FL, Cuthbertson AG, Qiu BL. RNAi knock-down of the Bemisia tabaci Toll gene ( BtToll ) increases mortality after challenge with destruxin A. Mol Immunol 2017. [DOI: 10.1016/j.molimm.2017.06.031] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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20
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Yang Y, Wang Y, Li L, Chen F, Zhang P. Activation of the Toll-like receptor 8 pathway increases the immunogenicity of mesenchymal stem cells from umbilical cord. Mol Med Rep 2017; 16:2061-2068. [PMID: 28656222 DOI: 10.3892/mmr.2017.6806] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 03/21/2017] [Indexed: 02/05/2023] Open
Abstract
Mesenchymal stem cells (MSCs) are now widely used in clinical cell‑based therapy due to their characteristics of low immunogenicity, multiple differentiation potency and the capability to modulate immune responses. However, accumulated research has indicated the absence of engrafted MSCs because of the increased immunogenicity of MSCs. Toll‑like receptors (TLRs) are essential for the innate immune response and regulating the biological function of MSCs. The present study used human umbilical cord‑derived MSCs (UCMSCs) and activated the TLR8 pathway of UCMSCs to study the role of TLR8 in mediating the immune status of UCMSCs. The results demonstrated that the activation of TLR8 increased both the proliferation of peripheral blood mononuclear cells (PBMCs) isolated from healthy human volunteers and the release of lactate dehydrogenase (LDH) in supernatant from the PBMC‑UCMSCs co‑culture system. Reverse transcription-quantitative polymerase chain reaction indicated that the TLR8 agonist increased the expression of many co‑stimulatory molecules and pro‑inflammatory genes, and flow cytometry indicated that activation of the TLR8 agonist increased co‑stimulation protein levels but reduced specific surface markers, as confirmed by the part loss of stemness of UCMSCs. Finally, TLR8 increased osteocyte differentiation but had no effect on chondrocyte and adipocyte differentiation. The current study indicated the implication to TLR8 as regulators of the immunogenicity of UCMSCs.
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Affiliation(s)
- Yu Yang
- Department of Medical Oncology, Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Yanwen Wang
- Laboratory of Pathology, Department of Pathology, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Li Li
- Laboratory of Pathology, Department of Pathology, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Fei Chen
- Laboratory of Pathology, Department of Pathology, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
| | - Peng Zhang
- Department of Urology, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
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21
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Ma L, Yang J, Yang L, Shi J, Xue J, Li Y, Liu X. Developmental expression of Toll‑like receptors in the guinea pig lung. Mol Med Rep 2017; 15:1243-1251. [PMID: 28098883 PMCID: PMC5367368 DOI: 10.3892/mmr.2017.6129] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2015] [Accepted: 11/21/2016] [Indexed: 12/27/2022] Open
Abstract
The guinea pig is a useful model for investigating infectious and non‑infectious lung diseases due to the sensitivity of its respiratory system and susceptibility to infectious agents. Toll‑like receptors (TLRs) are important components of the innate immune response and are critical for lung immune function. In the present study, the differentiation of epithelial cells in the guinea pig lung was examined during gestation by studying anatomic morphology and the major epithelial cell types using cell type‑specific markers. The developmental expression of all 9 TLRs and the TLR signaling adaptors myeloid differentiation factor 88 (MyD88) and tumor necrosis factor receptor associated factor 6 (TRAF‑6) were investigated by reverse transcription‑quantitative polymerase chain reaction and western blotting analysis. The formation of lung lobes in guinea pigs was observed at 45 days of gestation (dGA), along with the expression of the basal cell marker keratin 14 and the alveolar type II cell marker pro‑surfactant protein. However, the cube cell marker secretoglobin family1A member 1 and ciliated cell marker b‑tubulin IV were only detected in the lungs from 52 dGA onward. The expression levels of all TLRs, MyD88 and TRAF‑6 were determined in lung tissues harvested from embryos, newborn, postnatal and adult animals. The expression levels of all TLR signaling components displayed similar dynamic expression patterns with gestation age and postnatal maturation time, except for TLR‑4 and TLR‑7. mRNA expression levels of TLR components were significantly increased in the lungs at 45 and 52 dGA, compared with later developmental stages. These results suggest that TLR expression in the guinea pig lung is developmentally regulated, enhancing the understanding of lung biology in guinea pig models.
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Affiliation(s)
- Lingjie Ma
- Key Laboratory of The Ministry of Education for The Conservation and Utilization of Special Biological Resources of Western China, Ningxia University, Yinchuan, Ningxia 750021, P.R. China
| | - Jiali Yang
- Ningxia Key Laboratory of Clinical and Pathogenic Microbiology, General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Li Yang
- The Center of Experimental Animals, Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Juan Shi
- Ningxia Key Laboratory of Clinical and Pathogenic Microbiology, General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750004, P.R. China
| | - Jing Xue
- Key Laboratory of The Ministry of Education for The Conservation and Utilization of Special Biological Resources of Western China, Ningxia University, Yinchuan, Ningxia 750021, P.R. China
| | - Yong Li
- Key Laboratory of The Ministry of Education for The Conservation and Utilization of Special Biological Resources of Western China, Ningxia University, Yinchuan, Ningxia 750021, P.R. China
| | - Xiaoming Liu
- Key Laboratory of The Ministry of Education for The Conservation and Utilization of Special Biological Resources of Western China, Ningxia University, Yinchuan, Ningxia 750021, P.R. China
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22
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Kong D, Wolf F, Großhans J. Forces directing germ-band extension in Drosophila embryos. Mech Dev 2016; 144:11-22. [PMID: 28013027 DOI: 10.1016/j.mod.2016.12.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Revised: 12/12/2016] [Accepted: 12/13/2016] [Indexed: 01/06/2023]
Abstract
Body axis elongation by convergent extension is a conserved developmental process found in all metazoans. Drosophila embryonic germ-band extension is an important morphogenetic process during embryogenesis, by which the length of the germ-band is more than doubled along the anterior-posterior axis. This lengthening is achieved by typical convergent extension, i.e. narrowing the lateral epidermis along the dorsal-ventral axis and simultaneous extension along the anterior-posterior axis. Germ-band extension is largely driven by cell intercalation, whose directionality is determined by the planar polarity of the tissue and ultimately by the anterior-posterior patterning system. In addition, extrinsic tensile forces originating from the invaginating endoderm induce cell shape changes, which transiently contribute to germ-band extension. Here, we review recent progress in understanding of the role of mechanical forces in germ-band extension.
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Affiliation(s)
- Deqing Kong
- Institute for Developmental Biochemistry, Medical School, University of Göttingen, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany
| | - Fred Wolf
- Department of Nonlinear Dynamics, Max Planck Institute for Dynamics and Self-Organisation, Faculty of Physics, Bernstein Center for Computational Neuroscience, University of Göttingen, Am Faßberg 17, 37077 Göttingen, Germany
| | - Jörg Großhans
- Institute for Developmental Biochemistry, Medical School, University of Göttingen, Justus-von-Liebig Weg 11, 37077 Göttingen, Germany.
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Abstract
The multifaceted response of the fruitfly Drosophila melanogaster to infection by a wide range of microbes is complex and remarkably efficient. Its most prominent aspect is the immune-inducible expression of a set of potent antimicrobial peptides. Genetic analysis of the regulation of the genes encoding these peptides has led to the identification of the receptor Toll as an essential component of the fly's host defense system. In addition, these studies have revealed that the response to Gram-negative bacterial infections involves Toll-independent mechanisms, and that the sensing of infection involves two structurally distinct sets of molecules — the PGRPs and the GNBPs/βGRPs.
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24
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Martinelli C, Reichhart JM. Evolution and integration of innate immune systems from fruit flies to man: lessons and questions. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/09680519050110041001] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Despite broad differences in morphology, ecology and behavior, the fruit fly Drosophila melanogaster and humans show a remarkably high degree of conservation for many molecular, cellular, and developmental aspects of their biology. During the last decade, similarities have also been discovered in some of the mechanisms regulating their innate immune system. These parallels regard mainly the Toll-like receptor family and the intracellular signaling pathways involved in the control of the immune response. However, if the overall similarities are important, the detailed pathogen recognition mechanisms differ significantly between fly and humans, highlighting a complicated evolutionary history of the metazoan innate defenses. In this review, we will discuss the main similarities and differences between the two types of organisms. We hope that this current knowledge will be used as a starting point for a more comprehensive view of innate immunity within the broad variety of metazoan phyla.
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Affiliation(s)
- Cosimo Martinelli
- UPR 9022 du CNRS, Institut de Biologie Moléculaire et Cellulaire (IBMC) 15, Strasbourg, France
| | - Jean-Marc Reichhart
- UPR 9022 du CNRS, Institut de Biologie Moléculaire et Cellulaire (IBMC) 15, Strasbourg, France, -strasbg.fr
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25
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Sun Y, Jiang Y, Wang Y, Li X, Yang R, Yu Z, Qin L. The Toll Signaling Pathway in the Chinese Oak Silkworm, Antheraea pernyi: Innate Immune Responses to Different Microorganisms. PLoS One 2016; 11:e0160200. [PMID: 27483463 PMCID: PMC4970820 DOI: 10.1371/journal.pone.0160200] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 07/16/2016] [Indexed: 11/19/2022] Open
Abstract
The Toll pathway is one of the most important signaling pathways regulating insect innate immunity. Spatzle is a key protein that functions as a Toll receptor ligand to trigger Toll-dependent expression of immunity-related genes. In this study, a novel spatzle gene (ApSPZ) from the Chinese oak silkworm Antheraea pernyi was identified. The ApSPZ cDNA is 1065 nucleotides with an open reading frame (ORF) of 777 bp encoding a protein of 258 amino acids. The protein has an estimated molecular weight of 29.71 kDa and an isoelectric point (PI) of 8.53. ApSPZ is a nuclear and secretory protein with no conserved domains or membrane helices and shares 40% amino acid identity with SPZ from Manduca sexta. Phylogenetic analysis indicated that ApSPZ might be a new member of the Spatzle type 1 family, which belongs to the Spatzle superfamily. The expression patterns of several genes involved in the Toll pathway were examined at different developmental stages and various tissues in 5th instar larvae. The examined targets included A. pernyi spatzle, GNBP, MyD88, Tolloid, cactus and dorsalA. The RT-PCR results showed that these genes were predominantly expressed in immune-responsive fat body tissue, indicating that the genes play a crucial role in A. pernyi innate immunity. Moreover, A. pernyi infection with the fungus Nosema pernyi and the gram-positive bacterium Enterococcus pernyi, but not the gram-negative bacterium Escherichia coli, activated the Toll signaling pathway. These results represent the first study of the Toll pathway in A. pernyi, which provides insight into the A. pernyi innate immune system.
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Affiliation(s)
- Ying Sun
- College of Plant Protection, Shenyang Agricultural University, Shenyang, 110866, China
- College of Bioscience and Biotechnology, Liaoning Engineering & Technology Research Center for Insect Resources, Shenyang Agricultural University, Shenyang, 110866, China
| | - Yiren Jiang
- College of Bioscience and Biotechnology, Liaoning Engineering & Technology Research Center for Insect Resources, Shenyang Agricultural University, Shenyang, 110866, China
| | - Yong Wang
- College of Bioscience and Biotechnology, Liaoning Engineering & Technology Research Center for Insect Resources, Shenyang Agricultural University, Shenyang, 110866, China
| | - Xisheng Li
- College of Plant Protection, Shenyang Agricultural University, Shenyang, 110866, China
- Sericultural Research Institute of Liaoning Province, Fengcheng, 118100, China
| | - Ruisheng Yang
- College of Bioscience and Biotechnology, Liaoning Engineering & Technology Research Center for Insect Resources, Shenyang Agricultural University, Shenyang, 110866, China
| | - Zhiguo Yu
- College of Plant Protection, Shenyang Agricultural University, Shenyang, 110866, China
- * E-mail: (ZY); (LQ)
| | - Li Qin
- College of Plant Protection, Shenyang Agricultural University, Shenyang, 110866, China
- College of Bioscience and Biotechnology, Liaoning Engineering & Technology Research Center for Insect Resources, Shenyang Agricultural University, Shenyang, 110866, China
- * E-mail: (ZY); (LQ)
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26
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Toll Genes Have an Ancestral Role in Axis Elongation. Curr Biol 2016; 26:1609-1615. [DOI: 10.1016/j.cub.2016.04.055] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 04/06/2016] [Accepted: 04/20/2016] [Indexed: 12/17/2022]
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27
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Analysis of the Contribution of Hemocytes and Autophagy to Drosophila Antiviral Immunity. J Virol 2016; 90:5415-5426. [PMID: 27009948 DOI: 10.1128/jvi.00238-16] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 03/16/2016] [Indexed: 02/07/2023] Open
Abstract
UNLABELLED Antiviral immunity in the model organism Drosophila melanogaster involves the broadly active intrinsic mechanism of RNA interference (RNAi) and virus-specific inducible responses. Here, using a panel of six viruses, we investigated the role of hemocytes and autophagy in the control of viral infections. Injection of latex beads to saturate phagocytosis, or genetic depletion of hemocytes, resulted in decreased survival and increased viral titers following infection with Cricket paralysis virus (CrPV), Flock House virus (FHV), and vesicular stomatitis virus (VSV) but had no impact on Drosophila C virus (DCV), Sindbis virus (SINV), and Invertebrate iridescent virus 6 (IIV6) infection. In the cases of CrPV and FHV, apoptosis was induced in infected cells, which were phagocytosed by hemocytes. In contrast, VSV did not trigger any significant apoptosis but we confirmed that the autophagy gene Atg7 was required for full virus resistance, suggesting that hemocytes use autophagy to recognize the virus. However, this recognition does not depend on the Toll-7 receptor. Autophagy had no impact on DCV, CrPV, SINV, or IIV6 infection and was required for replication of the sixth virus, FHV. Even in the case of VSV, the increases in titers were modest in Atg7 mutant flies, suggesting that autophagy does not play a major role in antiviral immunity in Drosophila Altogether, our results indicate that, while autophagy plays a minor role, phagocytosis contributes to virus-specific immune responses in insects. IMPORTANCE Phagocytosis and autophagy are two cellular processes that involve lysosomal degradation and participate in Drosophila immunity. Using a panel of RNA and DNA viruses, we have addressed the contribution of phagocytosis and autophagy in the control of viral infections in this model organism. We show that, while autophagy plays a minor role, phagocytosis contributes to virus-specific immune responses in Drosophila This work brings to the front a novel facet of antiviral host defense in insects, which may have relevance in the control of virus transmission by vector insects or in the resistance of beneficial insects to viral pathogens.
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Buckley KM, Rast JP. Diversity of animal immune receptors and the origins of recognition complexity in the deuterostomes. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2015; 49:179-189. [PMID: 25450907 DOI: 10.1016/j.dci.2014.10.013] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 10/01/2014] [Accepted: 10/20/2014] [Indexed: 06/04/2023]
Abstract
Invertebrate animals are characterized by extraordinary diversity in terms of body plan, life history and life span. The past impression that invertebrate immune responses are controlled by relatively simple innate systems is increasingly contradicted by genomic analyses that reveal significant evolutionary novelty and complexity. One accessible measure of this complexity is the multiplicity of genes encoding homologs of pattern recognition receptors. These multigene families vary significantly in size, and their sequence character suggests that they vary in function. At the same time, certain aspects of downstream signaling appear to be conserved. Here, we analyze five major classes of immune recognition receptors from newly available animal genome sequences. These include the Toll-like receptors (TLR), Nod-like receptors (NLR), SRCR domain scavenger receptors, peptidoglycan recognition proteins (PGRP), and Gram negative binding proteins (GNBP). We discuss innate immune complexity in the invertebrate deuterostomes, which was first recognized in sea urchins, within the wider context of emerging genomic information across animal phyla.
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MESH Headings
- Animals
- Biodiversity
- Evolution, Molecular
- Genetic Variation
- Genome/genetics
- Immunity, Innate/genetics
- Immunity, Innate/immunology
- Invertebrates/classification
- Invertebrates/genetics
- Invertebrates/immunology
- Multigene Family/genetics
- Multigene Family/immunology
- Phylogeny
- Receptors, Immunologic/classification
- Receptors, Immunologic/genetics
- Receptors, Immunologic/immunology
- Receptors, Pattern Recognition/genetics
- Receptors, Pattern Recognition/immunology
- Receptors, Scavenger/genetics
- Receptors, Scavenger/immunology
- Species Specificity
- Toll-Like Receptors/genetics
- Toll-Like Receptors/immunology
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Affiliation(s)
- Katherine M Buckley
- Department of Immunology and Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada; Sunnybrook Research Institute, Toronto, ON, Canada.
| | - Jonathan P Rast
- Department of Immunology and Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada; Sunnybrook Research Institute, Toronto, ON, Canada
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Kannaki TR, Reddy MR, Verma PC, Shanmugam M. Differential Toll-Like Receptor (TLR) mRNA Expression Patterns during Chicken Embryological Development. Anim Biotechnol 2014; 26:130-5. [DOI: 10.1080/10495398.2014.939658] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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A positional Toll receptor code directs convergent extension in Drosophila. Nature 2014; 515:523-7. [PMID: 25363762 DOI: 10.1038/nature13953] [Citation(s) in RCA: 178] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 10/09/2014] [Indexed: 12/21/2022]
Abstract
Elongation of the head-to-tail body axis by convergent extension is a conserved developmental process throughout metazoans. In Drosophila, patterns of transcription factor expression provide spatial cues that induce systematically oriented cell movements and promote tissue elongation. However, the mechanisms by which patterned transcriptional inputs control cell polarity and behaviour have long been elusive. We demonstrate that three Toll family receptors, Toll-2, Toll-6 and Toll-8, are expressed in overlapping transverse stripes along the anterior-posterior axis and act in combination to direct planar polarity and polarized cell rearrangements during convergent extension. Simultaneous disruption of all three receptors strongly reduces actomyosin-driven junctional remodelling and axis elongation, and an ectopic stripe of Toll receptor expression is sufficient to induce planar polarized actomyosin contractility. These results demonstrate that tissue-level patterns of Toll receptor expression provide spatial signals that link positional information from the anterior-posterior patterning system to the essential cell behaviours that drive convergent extension.
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Liu J, Kolliopoulou A, Smagghe G, Swevers L. Modulation of the transcriptional response of innate immune and RNAi genes upon exposure to dsRNA and LPS in silkmoth-derived Bm5 cells overexpressing BmToll9-1 receptor. JOURNAL OF INSECT PHYSIOLOGY 2014; 66:10-19. [PMID: 24831177 DOI: 10.1016/j.jinsphys.2014.05.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 05/04/2014] [Accepted: 05/06/2014] [Indexed: 06/03/2023]
Abstract
Injection or feeding of dsRNA is commonly used to induce specific gene silencing by RNAi in insects but very little research has been carried out to investigate non-specific effects on gene expression of dsRNA as pathogen-associated molecular pattern (PAMP). This study focuses on the potential role of the BmToll9-1 receptor to modulate the transcriptional response of innate immune and RNAi genes to dsRNA and lipopolysaccharide (LPS), which was used for comparison. To study this role, we took advantage of the silkmoth-derived Bm5 cell line, which does not express BmToll9-1 endogenously, and engineered a transformed cell line that permanently expresses BmToll9-1. Quantitative mRNA expression studies showed that BmToll9-1 can significantly alter the transcriptional response to dsRNA and LPS: (1) BmToll9-1 promotes the transcriptional response of Dicer2, encoding a key component of the RNAi machinery, and, to a lesser extent, that of transcription factors in the Jak-STAT and Toll pathways; and (2) BmToll9-1 represses the transcriptional induction of the IMD and Jak-STAT pathway genes, as well as the antimicrobial peptide (AMP) effector genes, by LPS. Thus, BmToll9-1 was identified as a modulator of innate immune and RNAi machinery gene expression that could be related to its preferential expression in the larval gut, the major barrier of pathogen entry. While BmToll9-1 was found to modulate RNAi-related gene expression, a reporter-based RNAi assay established no evidence for a direct interaction of BmToll9-1 with the intracellular RNAi machinery.
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Affiliation(s)
- Jisheng Liu
- Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Anna Kolliopoulou
- Insect Molecular Genetics and Biotechnology, Institute of Biosciences & Applications, National Centre for Scientific Research "Demokritos", Athens, Greece
| | - Guy Smagghe
- Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.
| | - Luc Swevers
- Insect Molecular Genetics and Biotechnology, Institute of Biosciences & Applications, National Centre for Scientific Research "Demokritos", Athens, Greece.
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Browne N, Heelan M, Kavanagh K. An analysis of the structural and functional similarities of insect hemocytes and mammalian phagocytes. Virulence 2013; 4:597-603. [PMID: 23921374 PMCID: PMC3906293 DOI: 10.4161/viru.25906] [Citation(s) in RCA: 213] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 07/24/2013] [Accepted: 07/25/2013] [Indexed: 11/29/2022] Open
Abstract
The insect immune response demonstrates a number of structural and functional similarities to the innate immune system of mammals. As a result of these conserved features insects have become popular choices for evaluating the virulence of microbial pathogens or for assessing the efficacy of antimicrobial agents and give results which are comparable to those that can be obtained using mammals. Analysis of the cellular component of the insect and mammalian immune systems demonstrates many similarities. Insect hemocytes recognize pathogens and phagocytose material in a similar manner to neutrophils. The killing of ingested microbes is achieved in both cell types by the production of superoxide and by the release of enzymes in the process of degranulation. Insect hemocytes and mammalian neutrophils are sensitive to the same inhibitors. This review highlights the strong similarities between the phagocytic cells of both groups of animals and demonstrates the potential benefits of using selected insects as in vivo screening systems.
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Affiliation(s)
- Niall Browne
- Department of Biology; NUI Maynooth; Maynooth, Co. Kildare Ireland
| | - Michelle Heelan
- Department of Biology; NUI Maynooth; Maynooth, Co. Kildare Ireland
| | - Kevin Kavanagh
- Department of Biology; NUI Maynooth; Maynooth, Co. Kildare Ireland
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McIlroy G, Foldi I, Aurikko J, Wentzell JS, Lim MA, Fenton JC, Gay NJ, Hidalgo A. Toll-6 and Toll-7 function as neurotrophin receptors in the Drosophila melanogaster CNS. Nat Neurosci 2013; 16:1248-56. [PMID: 23892553 PMCID: PMC4634317 DOI: 10.1038/nn.3474] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 06/20/2013] [Indexed: 02/07/2023]
Abstract
Neurotrophin receptors corresponding to vertebrate Trk, p75NTR or Sortilin have not been identified in Drosophila, thus it is unknown how neurotrophism may be implemented in insects. Two Drosophila neurotrophins, DNT1 and DNT2, have nervous system functions, but their receptors are unknown. The Toll receptor superfamily has ancient evolutionary origins and a universal function in innate immunity. Here we show that Toll paralogues unrelated to the mammalian neurotrophin receptors function as neurotrophin receptors in fruit-flies. Toll-6 and Toll-7 are expressed in the central nervous system throughout development, and regulate locomotion, motoraxon targeting and neuronal survival. DNT1 and 2 interact genetically with Toll-6 and 7, bind to Toll-7 and 6 promiscuously, and are distributed in vivo in complementary or overlapping domains. We conclude that in fruit-flies, Tolls are not only involved in development and immunity but also in neurotrophism, revealing an unforeseen relationship between the neurotrophin and Toll protein families.
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Affiliation(s)
- Graham McIlroy
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
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Sundaram AYM, Kiron V, Dopazo J, Fernandes JMO. Diversification of the expanded teleost-specific toll-like receptor family in Atlantic cod, Gadus morhua. BMC Evol Biol 2012; 12:256. [PMID: 23273344 PMCID: PMC3549756 DOI: 10.1186/1471-2148-12-256] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 12/26/2012] [Indexed: 01/19/2023] Open
Abstract
Background Toll-like receptors (Tlrs) are major molecular pattern recognition receptors of the innate immune system. Atlantic cod (Gadus morhua) is the first vertebrate known to have lost most of the mammalian Tlr orthologues, particularly all bacterial recognising and other cell surface Tlrs. On the other hand, its genome encodes a unique repertoire of teleost-specific Tlrs. The aim of this study was to investigate if these duplicate Tlrs have been retained through adaptive evolution to compensate for the lack of other cell surface Tlrs in the cod genome. Results In this study, one tlr21, 12 tlr22 and two tlr23 genes representing the teleost-specific Tlr family have been cloned and characterised in cod. Phylogenetic analysis grouped all tlr22 genes under a single clade, indicating that the multiple cod paralogues have arisen through lineage-specific duplications. All tlrs examined were transcribed in immune-related tissues as well as in stomach, gut and gonads of adult cod and were differentially expressed during early development. These tlrs were also differentially regulated following immune challenge by immersion with Vibrio anguillarum, indicating their role in the immune response. An increase in water temperature from 4 to 12°C was associated with a 5.5-fold down-regulation of tlr22d transcript levels in spleen. Maximum likelihood analysis with different evolution models revealed that tlr22 genes are under positive selection. A total of 24 codons were found to be positively selected, of which 19 are in the ligand binding region of ectodomain. Conclusion Positive selection pressure coupled with experimental evidence of differential expression strongly support the hypothesis that teleost-specific tlr paralogues in cod are undergoing neofunctionalisation and can recognise bacterial pathogen-associated molecular patterns to compensate for the lack of other cell surface Tlrs.
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Affiliation(s)
- Arvind Y M Sundaram
- Faculty of Biosciences and Aquaculture, University of Nordland, Bodø, Norway
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MyD88-deficient Hydra reveal an ancient function of TLR signaling in sensing bacterial colonizers. Proc Natl Acad Sci U S A 2012; 109:19374-9. [PMID: 23112184 DOI: 10.1073/pnas.1213110109] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Toll-like receptor (TLR) signaling is one of the most important signaling cascades of the innate immune system of vertebrates. Studies in invertebrates have focused on the fruit fly Drosophila melanogaster and the nematode Caenorhabditis elegans, and there is little information regarding the evolutionary origin and ancestral function of TLR signaling. In Drosophila, members of the Toll-like receptor family are involved in both embryonic development and innate immunity. In C. elegans, a clear immune function of the TLR homolog TOL-1 is controversial and central components of vertebrate TLR signaling including the key adapter protein myeloid differentiation primary response gene 88 (MyD88) and the transcription factor NF-κB are not present. In basal metazoans such as the cnidarians Hydra magnipapillata and Nematostella vectensis, all components of the vertebrate TLR signaling cascade are present, but their role in immunity is unknown. Here, we use a MyD88 loss-of-function approach in Hydra to demonstrate that recognition of bacteria is an ancestral function of TLR signaling and that this process contributes to both host-mediated recolonization by commensal bacteria as well as to defense against bacterial pathogens.
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Nicol-Benoît F, Le-Goff P, Le-Dréan Y, Demay F, Pakdel F, Flouriot G, Michel D. Epigenetic memories: structural marks or active circuits? Cell Mol Life Sci 2012; 69:2189-203. [PMID: 22331281 PMCID: PMC11114908 DOI: 10.1007/s00018-012-0923-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 12/06/2011] [Accepted: 01/10/2012] [Indexed: 12/22/2022]
Abstract
A hallmark of living systems is the management and the storage of information through genetic and epigenetic mechanisms. Although the notion of epigenetics was originally given to any regulation beyond DNA sequence, it has often been restricted to chromatin modifications, supposed to behave as cis-markers, specifying the sets of genes to be expressed or repressed. This definition does not take into account the initial view of epigenetics, based on nonlinear interaction networks whose "attractors" can remain stable without need for any chromatin mark. In addition, most chromatin modifications are the steady state resultants of highly dynamic modification and de-modification activities and, as such, seem poorly appropriate to work as long-term memory keepers. Instead, the basic support of epigenetic memory could remain the attractors, to which chromatin modifications belong as do many other components. The influence of chromatin modifications in memory is highly questionable when envisioned as static structural marks, but can be recovered under the dynamic circuitry perspective, thanks to their self-templating properties. Beside their standard repressive or permissive functions, chromatin modifications can also influence transcription in multiple ways such as: (1) by randomizing or inversely stabilizing gene expression, (2) by mediating cooperativity between pioneer and secondary transcription factors, and (3) in the hysteresis and the ultrasensitivity of gene expression switches, allowing the cells to take unambiguous transcriptional decisions.
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Affiliation(s)
- Floriane Nicol-Benoît
- Université de Rennes1, Irset. IFR-GFAS Campus de Beaulieu. Bat.13, 35042 Rennes cedex, France
| | - Pascale Le-Goff
- Université de Rennes1, Irset. IFR-GFAS Campus de Beaulieu. Bat.13, 35042 Rennes cedex, France
| | - Yves Le-Dréan
- Université de Rennes1, Irset. IFR-GFAS Campus de Beaulieu. Bat.13, 35042 Rennes cedex, France
| | - Florence Demay
- Université de Rennes1, Irset. IFR-GFAS Campus de Beaulieu. Bat.13, 35042 Rennes cedex, France
| | - Farzad Pakdel
- Université de Rennes1, Irset. IFR-GFAS Campus de Beaulieu. Bat.13, 35042 Rennes cedex, France
| | - Gilles Flouriot
- Université de Rennes1, Irset. IFR-GFAS Campus de Beaulieu. Bat.13, 35042 Rennes cedex, France
| | - Denis Michel
- Université de Rennes1, Irset. IFR-GFAS Campus de Beaulieu. Bat.13, 35042 Rennes cedex, France
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Marek LR, Kagan JC. Phosphoinositide binding by the Toll adaptor dMyD88 controls antibacterial responses in Drosophila. Immunity 2012; 36:612-22. [PMID: 22464168 DOI: 10.1016/j.immuni.2012.01.019] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2011] [Revised: 01/17/2012] [Accepted: 01/31/2012] [Indexed: 01/09/2023]
Abstract
The cell biological principles that govern innate immune responses in Drosophila are unknown. Here, we report that Toll signaling in flies was dictated by the subcellular localization of the adaptor protein dMyD88. dMyD88 was located at the plasma membrane by a process dependent on a C-terminal phosphoinositide-binding domain. In vivo analysis revealed that lipid binding by dMyD88 was necessary for its antimicrobial and developmental functions as well as for the recruitment of the downstream cytosolic adaptor Tube to the cell surface. These data are reminiscent of the interactions between the mammalian Toll adaptors MyD88 and TIRAP with one major exception. In the mammalian system, MyD88 is the cytosolic adaptor that depends on the phosphoinositide-binding protein TIRAP for its recruitment to the cell surface. We therefore propose that dMyD88 is the functional homolog of TIRAP and that both proteins function as sorting adaptors to recruit downstream signaling adaptors to activated receptors.
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Affiliation(s)
- Lorri R Marek
- Division of Gasteroenterology, Children's Hospital Boston, Harvard Medical School, Boston, MA 02115, USA
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Wu D, Luo XL, Lin Y, Fang ZF, Luo XR, Xu HT, Zeng W. Effects of vitamin E on reproductive protection in pregnant mice infected with pseudorabies virus (PRV) via regulating expression of Toll-like receptors (TLRs) and cytokine balance. J Nutr Sci Vitaminol (Tokyo) 2011; 56:353-63. [PMID: 21422704 DOI: 10.3177/jnsv.56.353] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Vitamin E supplement and pseudorabies virus (PRV) infection have a reciprocal role in influencing the maternal immune response, a key determinant of the success or failure of pregnancy. However, it remains unknown whether vitamin E supplement provides protection against PRV-induced failure of pregnancy. This study was therefore conducted to investigate the effect of dietary vitamin E level (0, 75, 375, 750 and 1,500 mg/kg) on the reproduction performance, immunity and expression of Toll-like receptors (TLRs) of PRV-challenged mice. The mortality and abortion rate of PRV-challenged mice decreased with the increase in vitamin E consumption. Overall, PBS-injected mice had a higher live embryo number and live litter size than PRV-challenged mice. Both live embryo number and live litter size of PRV-challenged mice increased with increasing vitamin E levels. Vitamin E supplement resulted in decreased concentration of serum IL-2 and IFN-γ, but increased concentration of serum IL-10. The concentration of serum IgG, IgA and IgM increased with increasing vitamin E levels. In the uterine and embryo mRNA abundance of TLR3, TLR7 and TLR9 was higher in PRV-challenged mice than that in PBS-injected mice fed on the same dosage of vitamin E. The mRNA abundance of embryonic TLR3, TLR7 and TLR9 in PRV-challenged mice decreased with increasing vitamin E levels. Collectively, vitamin E supplement may improve reproductive performance of PRV-challenged mice by attenuating PRV-induced negative effects on the cytokine profile, immunoglobulin synthesis and TLR expression.
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Affiliation(s)
- De Wu
- Key Laboratory for Animal Disease Resistance Nutrition of the Ministry of Education of China, Sichuan Agricultural University, Ya'an, Sichuan, China
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Ben-Ami R. Innate Immunity Against Moulds: Lessons Learned from Invertebrate Models. Immunol Invest 2011; 40:676-91. [DOI: 10.3109/08820139.2011.587218] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Ronen Ben-Ami
- Infectious Disease Unit, Tel Aviv Sourasky Medical Center,
Tel Aviv, Israel
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Avlas O, Fallach R, Shainberg A, Porat E, Hochhauser E. Toll-like receptor 4 stimulation initiates an inflammatory response that decreases cardiomyocyte contractility. Antioxid Redox Signal 2011; 15:1895-909. [PMID: 21126202 DOI: 10.1089/ars.2010.3728] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Toll-like receptors (TLRs) have been identified as primary innate immune receptors for the recognition of pathogen-associated molecular patterns by immune cells, initiating a primary response toward invading pathogens and recruitment of the adaptive immune response. TLRs, especially Toll-like receptor 4 (TLR4), can also be stimulated by host-derived molecules and are expressed in the cardiovascular system, thus acting as a possible key link between cardiovascular diseases and the immune system. TLR4 is involved in the acute myocardial dysfunction caused by septic shock and myocardial ischemia. We used wild-type (WT) mice, TLR4-deficient (TLR4-knockout [ko]) mice, and chimeras that underwent myeloablative bone marrow transplantation to dissociate between TLR4 expression in the heart (TLR4-ko/WT) and the immunohematopoietic system (WT/TLR4-ko). Following lipopolysaccharide (LPS) challenge (septic shock model) or coronary artery ligation, myocardial ischemia (MI) model, we found WT/TLR4-ko mice challenged with LPS or MI displayed reduced cardiac function, increased myocardial levels of interleukin-1β and tumor necrosis factor-α, and upregulation of mRNA encoding TLR4 prior to myocardial leukocyte infiltration. The cardiac function of TLR4-ko or WT/TLR4-ko mice was less affected by LPS and demonstrated reduced suppression by MI compared with WT. These results suggest that TLR4 expressed in the cardiomyocytes plays a key role in this acute phenomenon.
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Affiliation(s)
- Orna Avlas
- Gonda (Goldschmied) Medical Diagnostic Research Center, The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
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Abstract
The Drosophila genome encodes a total of nine Toll and related proteins. The immune and developmental functions of Toll and 18Wheeler (18W) have been analyzed extensively, while the in vivo functions of the other Toll-related proteins require further investigation. We performed transgenic experiments and found that overexpression of Toll-related genes caused different extents of lethality and developmental defects. Moreover, 18w, Toll-6, Toll-7 and Toll-8 often caused related phenotypic changes, consistent with the idea that these four genes have more conserved molecular structure and thus may regulate similar processes in vivo. Deletion alleles of Toll-6, Toll-7 and Toll-8 were generated by targeted homologous recombination or P element excision. These mutant alleles were viable, fertile, and had no detectable defect in the inducible expression of antimicrobial peptide genes except for the Toll-8 mutant had some defects in leg development. The expression of 18w, Toll-7 and Toll-8 mRNA showed wide and overlapping patterns in imaginal discs and the 18w, Toll-8 double and Toll-7, Toll-8 double mutants showed substantially increased lethality. Overall our results suggest that some of the Toll-related proteins, such as 18W, Toll-7 and Toll-8, may have redundant functions in regulating developmental processes.
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Affiliation(s)
- Yoshimasa Yagi
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
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Narbonne-Reveau K, Charroux B, Royet J. Lack of an antibacterial response defect in Drosophila Toll-9 mutant. PLoS One 2011; 6:e17470. [PMID: 21386906 PMCID: PMC3046252 DOI: 10.1371/journal.pone.0017470] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Accepted: 02/02/2011] [Indexed: 01/12/2023] Open
Abstract
Toll and Toll-like receptors represent families of receptors involved in mediating innate immunity response in insects and mammals. Although Drosophila proteome contains multiple Toll paralogs, Toll-1 is, so far, the only receptor to which an immune role has been attributed. In contrast, every single mammalian TLR is a key membrane receptor upstream of the vertebrate immune signaling cascades. The prevailing view is that TLR-mediated immunity is ancient. Structural analysis reveals that Drosophila Toll-9 is the most closely related to vertebrate TLRs and utilizes similar signaling components as Toll-1. This suggests that Toll-9 could be an ancestor of TLR-like receptors and could have immune function. Consistently, it has been reported that over-expression of Toll-9 in immune tissues is sufficient to induce the expression of some antimicrobial peptides in flies. These results have led to the idea that Toll-9 could be a constitutively active receptor that maintain significant levels of antimicrobial molecules and therefore provide constant basal protection against micro-organisms. To test theses hypotheses, we generated and analyzed phenotypes associated with a complete loss-of-function allele of Toll-9. Our results suggest that Toll-9 is neither required to maintain a basal anti-microbial response nor to mount an efficient immune response to bacterial infection.
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Affiliation(s)
- Karine Narbonne-Reveau
- Institut de Biologie du Développement de Marseille-Luminy (IBDML), CNRS UMR 6216/Aix-Marseille II University, Campus de Luminy, Marseille, France
| | - Bernard Charroux
- Institut de Biologie du Développement de Marseille-Luminy (IBDML), CNRS UMR 6216/Aix-Marseille II University, Campus de Luminy, Marseille, France
| | - Julien Royet
- Institut de Biologie du Développement de Marseille-Luminy (IBDML), CNRS UMR 6216/Aix-Marseille II University, Campus de Luminy, Marseille, France
- * E-mail:
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Transcriptional profiling of Toll-like receptors in chicken embryos and in the ovary during sexual maturation and in response to Salmonella enteritidis infection. Anim Reprod Sci 2010; 122:294-302. [DOI: 10.1016/j.anireprosci.2010.09.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Revised: 09/01/2010] [Accepted: 09/17/2010] [Indexed: 11/17/2022]
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Zhang Q, Zmasek CM, Godzik A. Domain architecture evolution of pattern-recognition receptors. Immunogenetics 2010; 62:263-72. [PMID: 20195594 PMCID: PMC2858798 DOI: 10.1007/s00251-010-0428-1] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Accepted: 02/03/2010] [Indexed: 12/11/2022]
Abstract
In animals, the innate immune system is the first line of defense against invading microorganisms, and the pattern-recognition receptors (PRRs) are the key components of this system, detecting microbial invasion and initiating innate immune defenses. Two families of PRRs, the intracellular NOD-like receptors (NLRs) and the transmembrane Toll-like receptors (TLRs), are of particular interest because of their roles in a number of diseases. Understanding the evolutionary history of these families and their pattern of evolutionary changes may lead to new insights into the functioning of this critical system. We found that the evolution of both NLR and TLR families included massive species-specific expansions and domain shuffling in various lineages, which resulted in the same domain architectures evolving independently within different lineages in a process that fits the definition of parallel evolution. This observation illustrates both the dynamics of the innate immune system and the effects of "combinatorially constrained" evolution, where existence of the limited numbers of functionally relevant domains constrains the choices of domain architectures for new members in the family, resulting in the emergence of independently evolved proteins with identical domain architectures, often mistaken for orthologs.
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Affiliation(s)
- Qing Zhang
- Burnham Institute for Medical Research, 10901 North Torrey Pines Road, La Jolla, CA 92037 USA
| | - Christian M. Zmasek
- Burnham Institute for Medical Research, 10901 North Torrey Pines Road, La Jolla, CA 92037 USA
| | - Adam Godzik
- Burnham Institute for Medical Research, 10901 North Torrey Pines Road, La Jolla, CA 92037 USA
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093 USA
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Hetru C, Hoffmann JA. NF-kappaB in the immune response of Drosophila. Cold Spring Harb Perspect Biol 2009; 1:a000232. [PMID: 20457557 DOI: 10.1101/cshperspect.a000232] [Citation(s) in RCA: 180] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The nuclear factor kappaB (NF-kappaB) pathways play a major role in Drosophila host defense. Two recognition and signaling cascades control this immune response. The Toll pathway is activated by Gram-positive bacteria and by fungi, whereas the immune deficiency (Imd) pathway responds to Gram-negative bacterial infection. The basic mechanisms of recognition of these various types of microbial infections by the adult fly are now globally understood. Even though some elements are missing in the intracellular pathways, numerous proteins and interactions have been identified. In this article, we present a general picture of the immune functions of NF-kappaB in Drosophila with all the partners involved in recognition and in the signaling cascades.
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Affiliation(s)
- Charles Hetru
- Centre National de la Recherche Scientifique, Institute of Molecular and Cellular Biology, 15 rue René Descartes, 67084 Strasbourg, France
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Sanyal S. Genomic mapping and expression patterns of C380, OK6 and D42 enhancer trap lines in the larval nervous system of Drosophila. Gene Expr Patterns 2009; 9:371-80. [PMID: 19602393 DOI: 10.1016/j.gep.2009.01.002] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2008] [Revised: 01/14/2009] [Accepted: 01/17/2009] [Indexed: 01/12/2023]
Abstract
Since its description more than fifteen years ago, the GAL4-UAS system of heterologous transgenic expression has found universal and widespread use in Drosophila research , making it a uniquely powerful analytical tool. Several hundreds of enhancer-trap GAL4 "driver" lines have since been used to express proteins of interest in specific spatio-temporal domains. However, the identities of enhancer elements that regulate GAL4 expression in vivo are often not known. Here, I report the mapping of three GAL4 lines commonly used as motor neuron drivers. Sequencing of genomic DNA flanking these three P-element transposon insertion, C380, (BG380), OK6, and D42, shows that these insertions lie upstream of the futsch, Rapgap 1 and toll-6 gene, respectively . Of the three, OK6-GAL4 (Rapgap 1) expression is most restricted to motor neurons, while C380-GAL4 and D42-GAL4 also show prominent expression in the peripheral nervous system, including body wall sensory nervous system. Albeit with clear differences. Finally, I test if the highly restricted expression pattern of Futsch is maintained in six other species of Drosophilids (D. yakuba, D. ananssae, D.pseudoobscura, D. dimulars, D. willistoni and D. virilis). My results suggest conserved control of Futsch expression across species, most likely through upstream cis-acting elements. A comparative anatomy of the laval central nervous systems and peripheral innervation in these Frosophilids species as revealed by contemporary immunohistochemical markers is also presented.
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Affiliation(s)
- Subhabrata Sanyal
- Department of Cell Biology, Emory University of Medicine, Room No. 444, 615 ichael Street, NE, Atlanta, GA 30322, USA.
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Abstract
The epithelial layer occupies a strategic important location between an organisms' interior and exterior environment. Although as such it forms a physical barrier between both environments, it became clear that the role of the epithelium extends far beyond this rather passive role. Through specialized receptors and other more general mechanisms, the epithelial layer is not only able to sense changes in its environment but also to actively respond to these changes. These responses allow the epithelium to contribute to wound and tissue repair, to the defense against micro-organisms, and to the control and regulation of the locale immune response. In this review, we focus on signals acting on epithelium from the exterior environment, how these signals are processed and identify research challenges.
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Affiliation(s)
- A B Vroling
- Amsterdam Medical Center, Department of Otorhinolaryngology, Amsterdam, the Netherlands
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Richards JS, Liu Z, Shimada M. Immune-like mechanisms in ovulation. Trends Endocrinol Metab 2008; 19:191-6. [PMID: 18407514 DOI: 10.1016/j.tem.2008.03.001] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2008] [Revised: 03/11/2008] [Accepted: 03/11/2008] [Indexed: 01/12/2023]
Abstract
Ovulation is the unique biological process by which a mature oocyte (egg) and surrounding somatic cells, the cumulus cell-oocyte complex (COC), are released from the surface of the ovary into the oviduct for transport and fertilization. Ovulation is similar to an inflammatory response: the follicles become hyperemic, produce prostaglandins and synthesize a hyaluronan-rich extracellular matrix. However, this view of ovulation might be too restrictive and needs to be broadened to encompass the innate immune cell surveillance-response system. This hypothesis is being proposed because ovarian granulosa cells and cumulus cells express and respond to innate immune cell-related surveillance proteins (Toll-like receptors 2 and 4) and cytokines, such as interleukin 6 (IL-6), during ovulation.
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Affiliation(s)
- JoAnne S Richards
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA.
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Liu Z, Shimada M, Richards JS. The involvement of the Toll-like receptor family in ovulation. J Assist Reprod Genet 2008; 25:223-8. [PMID: 18509754 PMCID: PMC2582080 DOI: 10.1007/s10815-008-9219-0] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2008] [Accepted: 03/29/2008] [Indexed: 01/22/2023] Open
Abstract
INTRODUCTION Ovulation is similar to an inflammatory response and is associated with increased production of prostaglandins as well as local growth regulatory factors. However, the expression and function of innate immune cell-related genes in non-immune cells within the ovary has been reported recently and provides a novel and important regulatory system during ovulation. DISCUSSION Several members of the Toll-like receptor (TLR) surveillance system are expressed in granulosa cells and cumulus cells. These receptors can be activated by pathogens as well as endogenous ligands leading to the induction and release of potent cytokines and chemokines from cumulus cells. CONCLUSION These inflammatory factors exert potent effects on cumulus cell-oocyte expansion, ovulation, transport and fertilization indicating that ovulation is a more complex immune-inflammatory process than previously recognized.
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Affiliation(s)
- Zhilin Liu
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX USA
| | - Masayuki Shimada
- Graduate School of Biosphere Sciences, Hiroshima University, Hiroshima, Japan
| | - JoAnne S. Richards
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX USA
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