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Ren Y, Fu S, Dong W, Chen J, Xue H, Bu W. The ncRNA-mediated regulatory networks of defensins and lysozymes in Riptortus pedestris: involvement in response to gut bacterial disturbances. Front Microbiol 2024; 15:1386345. [PMID: 38827147 PMCID: PMC11140134 DOI: 10.3389/fmicb.2024.1386345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 04/23/2024] [Indexed: 06/04/2024] Open
Abstract
Insects depend on humoral immunity against intruders through the secretion of antimicrobial peptides (AMPs) and immune effectors via NF-κB transcription factors, and their fitness is improved by gut bacterial microbiota. Although there are growing numbers of reports on noncoding RNAs (ncRNAs) involving in immune responses against pathogens, comprehensive studies of ncRNA-AMP regulatory networks in Riptortus pedestris, which is one of the widely distributed pests in East Asia, are still not well understood under feeding environmental changes. The objective of this study employed the whole-transcriptome sequencing (WTS) to systematically identify the lncRNAs (long noncoding RNA) and circRNAs (circular RNA) and to obtain their differential expression from the R. pedestris gut under different feeding conditions. Functional annotation indicated that they were mainly enriched in various biological processes with the GO and KEGG databases, especially in immune signaling pathways. Five defensin (four novel members) and eleven lysozyme (nine novel members) family genes were identified and characterized from WTS data, and meanwhile, phylogenetic analysis confirmed their classification. Subsequently, the miRNA-mRNA interaction network of above two AMPs and lncRNA-involved ceRNA (competing endogenous RNA) regulatory network of one lysozyme were predicted and built based on bioinformatic prediction and calculation, and the expression patterns of differentially expressed (DE) defensins, and DE lysozymes and related DE ncRNAs were estimated and selected among all the comparison groups. Finally, to integrate the analyses of WTS and previous 16S rRNA amplicon sequencing, we conducted the Pearson correlation analysis to reveal the significantly positive or negative correlation between above DE AMPs and ncRNAs, as well as most changes in the gut bacterial microbiota at the genus level of R. pedestris. Taken together, the present observations provide great insights into the ncRNA regulatory networks of AMPs in response to rearing environmental changes in insects and uncover new potential strategies for pest control in the future.
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Affiliation(s)
- Yipeng Ren
- Institute of Entomology, College of Life Sciences, Nankai University, Tianjin, China
| | - Siying Fu
- Institute of Entomology, College of Life Sciences, Nankai University, Tianjin, China
| | - Wenhao Dong
- Tianjin Key Laboratory of Food and Biotechnology, School of Biotechnology and Food Science, Tianjin University of Commerce, Tianjin, China
| | - Juhong Chen
- Institute of Entomology, College of Life Sciences, Nankai University, Tianjin, China
| | - Huaijun Xue
- Institute of Entomology, College of Life Sciences, Nankai University, Tianjin, China
| | - Wenjun Bu
- Institute of Entomology, College of Life Sciences, Nankai University, Tianjin, China
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Ren Y, Dong W, Bu W, Xue H. Identification and expression patterns of somatic piRNAs and PIWI genes in Riptortus pedestris (Hemiptera: Alydidae). ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2024; 115:e22107. [PMID: 38591567 DOI: 10.1002/arch.22107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 02/29/2024] [Accepted: 03/15/2024] [Indexed: 04/10/2024]
Abstract
RNA interference (RNAi)-based gene silencing is a feasible and sustainable technology for the management of hemipteran pests by double-stranded RNA involvement, including small-interfering RNA, microRNA, and Piwi-interacting RNA (piRNA) pathways, that may help to decrease the usage of chemical insecticides. However, only a few data are available on the somatic piRNAs and their biogenesis genes in Riptortus pedestris, which serves as a significant pest of soybean (Glycine max). In this study, two family members of the PIWI gene were identified and characterized in R. pedestris, containing Argonaute3 (RpAgo3) and Aubergine (RpAub) genes with conserved protein domains, and their clusters were validated by phylogenetic analysis. In addition, they were widely expressed in all developmental stages of the whole body of R. pedestris and had lower expression levels in R. pedestris guts under different rearing conditions based on previous transcriptome sequencing. Furthermore, abundant clean reads were filtered to a total number of 45,998 piRNAs with uridine bias at the first nucleotide (nt) position and 26-32 nt in length by mapping onto the reference genome of R. pedestris according to our previous whole-transcriptome sequencing. Finally, our data revealed that gut bacterial changes were significantly positively or negatively associated with differentially expressed piRNAs among the five comparison groups with Pearson correlation analysis. In conclusion, these findings paved new avenues for the application of RNAi-based biopesticides for broad-spectrum hemipteran pest control.
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Affiliation(s)
- Yipeng Ren
- Institute of Entomology, College of Life Sciences, Nankai University, Tianjin, P.R. China
| | - Wenhao Dong
- Tianjin Key Laboratory of Food and Biotechnology, School of Biotechnology and Food Science, Tianjin University of Commerce, Tianjin, P.R. China
| | - Wenjun Bu
- Institute of Entomology, College of Life Sciences, Nankai University, Tianjin, P.R. China
| | - Huaijun Xue
- Institute of Entomology, College of Life Sciences, Nankai University, Tianjin, P.R. China
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Jang S, Ishigami K, Mergaert P, Kikuchi Y. Ingested soil bacteria breach gut epithelia and prime systemic immunity in an insect. Proc Natl Acad Sci U S A 2024; 121:e2315540121. [PMID: 38437561 PMCID: PMC10945853 DOI: 10.1073/pnas.2315540121] [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: 09/07/2023] [Accepted: 01/11/2024] [Indexed: 03/06/2024] Open
Abstract
Insects lack acquired immunity and were thought to have no immune memory, but recent studies reported a phenomenon called immune priming, wherein sublethal dose of pathogens or nonpathogenic microbes stimulates immunity and prevents subsequential pathogen infection. Although the evidence for insect immune priming is accumulating, the underlying mechanisms are still unclear. The bean bug Riptortus pedestris acquires its gut microbiota from ambient soil and spatially structures them into a multispecies and variable community in the anterior midgut and a specific, monospecies Caballeronia symbiont population in the posterior region. We demonstrate that a particular Burkholderia strain colonizing the anterior midgut stimulates systemic immunity by penetrating gut epithelia and migrating into the hemolymph. The activated immunity, consisting of a humoral and a cellular response, had no negative effect on the host fitness, but on the contrary protected the insect from subsequent infection by pathogenic bacteria. Interruption of contact between the Burkholderia strain and epithelia of the gut weakened the host immunity back to preinfection levels and made the insects more vulnerable to microbial infection, demonstrating that persistent acquisition of environmental bacteria is important to maintain an efficient immunity.
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Affiliation(s)
- Seonghan Jang
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Hokkaido Center, 062-8517Sapporo, Japan
| | - Kota Ishigami
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Hokkaido Center, 062-8517Sapporo, Japan
| | - Peter Mergaert
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, 91198Gif-sur-Yvette, France
| | - Yoshitomo Kikuchi
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Hokkaido Center, 062-8517Sapporo, Japan
- Unit of Applied Biological Chemistry, Graduate School of Agriculture, Hokkaido University, 060-8589Sapporo, Japan
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Abdullah SJ, Yan BTS, Palanivelu N, Dhanabal VB, Bifani JP, Bhattacharjya S. Outer-Membrane Permeabilization, LPS Transport Inhibition: Activity, Interactions, and Structures of Thanatin Derived Antimicrobial Peptides. Int J Mol Sci 2024; 25:2122. [PMID: 38396798 PMCID: PMC10888688 DOI: 10.3390/ijms25042122] [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: 01/11/2024] [Revised: 01/30/2024] [Accepted: 02/08/2024] [Indexed: 02/25/2024] Open
Abstract
Currently, viable antibiotics available to mitigate infections caused by drug-resistant Gram-negative bacteria are highly limited. Thanatin, a 21-residue-long insect-derived antimicrobial peptide (AMP), is a promising lead molecule for the potential development of novel antibiotics. Thanatin is extremely potent, particularly against the Enterobacter group of Gram-negative pathogens, e.g., E. coli and K. pneumoniae. As a mode of action, cationic thanatin efficiently permeabilizes the LPS-outer membrane and binds to the periplasmic protein LptAm to inhibit outer membrane biogenesis. Here, we have utilized N-terminal truncated 16- and 14-residue peptide fragments of thanatin and investigated structure, activity, and selectivity with correlating modes of action. A designed 16-residue peptide containing D-Lys (dk) named VF16 (V1PIIYCNRRT-dk-KCQRF16) demonstrated killing activity in Gram-negative bacteria. The VF16 peptide did not show any detectable toxicity to the HEK 293T cell line and kidney cell line Hep G2. As a mode of action, VF16 interacted with LPS, permeabilizing the outer membrane and binding to LptAm with high affinity. Atomic-resolution structures of VF16 in complex with LPS revealed cationic and aromatic surfaces involved in outer membrane interactions and permeabilization. Further, analyses of an inactive 14-residue native thanatin peptide (IM14: IIYCNRRTGKCQRM) delineated the requirement of the β-sheet structure in activity and target interactions. Taken together, this work would pave the way for the designing of short analogs of thanatin-based antimicrobials.
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Affiliation(s)
- Swaleeha Jaan Abdullah
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore; (S.J.A.); (N.P.)
| | - Bernice Tan Siu Yan
- A*Star Infectious Diseases Labs, 8A Biomedical Grove, Immunos, Singapore 138648, Singapore
| | - Nithya Palanivelu
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore; (S.J.A.); (N.P.)
| | - Vidhya Bharathi Dhanabal
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore; (S.J.A.); (N.P.)
| | - Juan Pablo Bifani
- A*Star Infectious Diseases Labs, 8A Biomedical Grove, Immunos, Singapore 138648, Singapore
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore
| | - Surajit Bhattacharjya
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore; (S.J.A.); (N.P.)
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Abdullah SJ, Mu Y, Bhattacharjya S. Structures, Interactions and Activity of the N-Terminal Truncated Variants of Antimicrobial Peptide Thanatin. Antibiotics (Basel) 2024; 13:74. [PMID: 38247633 PMCID: PMC10812785 DOI: 10.3390/antibiotics13010074] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Revised: 01/08/2024] [Accepted: 01/10/2024] [Indexed: 01/23/2024] Open
Abstract
Gram-negative bacteria are intrinsically more resistant to many frontline antibiotics, which is attributed to the permeability barrier of the outer membrane, drug efflux pumps and porins. Consequently, discovery of new small molecules antibiotics to kill drug-resistant Gram-negative bacteria presents a significant challenge. Thanatin, a 21-residue insect-derived antimicrobial peptide, is known for its potent activity against Enterobacter Gram-negative bacteria, including drug-resistant strains. Here, we investigated a 15-residue N-terminal truncated analog PM15 (P1IIYCNRRTGKCQRM15) of thanatin to determine modes of action and antibacterial activity. PM15 and the P1 to Y and A substituted variants PM15Y and PM15A delineated interactions and permeabilization of the LPS-outer membrane. In antibacterial assays, PM15 and the analogs showed growth inhibition of strains of Gram-negative bacteria that is largely dependent on the composition of the culture media. Atomic-resolution structures of PM15 and PM15Y in free solution and in complex with LPS micelle exhibited persistent β-hairpin structures similar to native thanatin. However, in complex with LPS, the structures of peptides are more compact, with extensive packing interactions among residues across the two anti-parallel strands of the β-hairpin. The docked complex of PM15/LPS revealed a parallel orientation of the peptide that may be sustained by potential ionic and van der Waals interactions with the lipid A moiety of LPS. Further, PM15 and PM15Y bind to LptAm, a monomeric functional variant of LptA, the periplasmic component of the seven-protein (A-G) complex involved in LPS transport. Taken together, the structures, target interactions and antibacterial effect of PM15 presented in the current study could be useful in designing thanatin-based peptide analogs.
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Affiliation(s)
| | | | - Surajit Bhattacharjya
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore; (S.J.A.); (Y.M.)
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Ren Y, Chen J, Fu S, Bu W, Xue H. Changes in the gut bacterial community affect miRNA profiles in Riptortus pedestris under different rearing conditions. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART D, GENOMICS & PROTEOMICS 2023; 48:101135. [PMID: 37688974 DOI: 10.1016/j.cbd.2023.101135] [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: 06/08/2023] [Revised: 08/04/2023] [Accepted: 08/31/2023] [Indexed: 09/11/2023]
Abstract
Insects possess complex and dynamic gut microbial system, which contributes to host nutrient absorption, reproduction, energy metabolism, and protection against stress. However, there are limited data on interactions of host-gut bacterial microbiota through miRNA (microRNA) regulation in a significant pest, Riptortus pedestris. Here, we performed the 16S rRNA amplicon sequencing and small RNA sequencing from the R. pedestris gut under three environmental conditions and antibiotic treatment, suggesting that we obtained a large amount of reads by assembly, filtration and quality control. The 16S rRNA amplicon sequencing results showed that the abundance and diversity of gut bacterial microbiota were significantly changed between antibiotic treatment and other groups, and they are involved in metabolism and biosynthesis-related function based on functional prediction. Furthermore, we identified different numbers of differentially expressed unigenes (DEGs) and differentially expressed miRNAs (DEMs) based on high-quality mappable reads, which were enriched in various immune-related pathways, including Toll-like receptor, RIG-I-like receptor, NOD-like receptor, JAK/STAT, PI3K/Akt, NF-κB, MAPK signaling pathways, and so forth, using GO and KEGG enrichment analysis. Later on, the identified miRNAs and their target genes in the R. pedestris gut were predicted and randomly selected to construct an interaction network. Finally, our study indicated that alterations in the gut bacterial microbiota are significantly positively or negatively associated with DEMs of the Toll/Imd signaling pathway with Pearson correlation analysis. Taken together, the results of our study lay the foundation for further deeply understanding the interactions between the gut microbiota and immune responses in R. pedestris through miRNA regulation, and provide the new basis for pest management in hemipteran pests.
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Affiliation(s)
- Yipeng Ren
- Institute of Entomology, College of Life Sciences, Nankai University, Tianjin 300071, PR China.
| | - Juhong Chen
- Institute of Entomology, College of Life Sciences, Nankai University, Tianjin 300071, PR China.
| | - Siying Fu
- Institute of Entomology, College of Life Sciences, Nankai University, Tianjin 300071, PR China.
| | - Wenjun Bu
- Institute of Entomology, College of Life Sciences, Nankai University, Tianjin 300071, PR China.
| | - Huaijun Xue
- Institute of Entomology, College of Life Sciences, Nankai University, Tianjin 300071, PR China.
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Lee J, Kim JU, Lee BL, Kim JK. Alteration of lipopolysaccharide O antigen leads to avirulence of gut-colonizing Serratia marcescens. Front Microbiol 2023; 14:1278917. [PMID: 38029092 PMCID: PMC10665507 DOI: 10.3389/fmicb.2023.1278917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 10/26/2023] [Indexed: 12/01/2023] Open
Abstract
The reason why the potent entomopathogen Serratia marcescens fails to kill insects through oral infection is unknown. To compare effects of septic injection and oral administration of S. marcescens, we used a model bean bug, Riptortus pedestris. Most R. pedestris insects survived oral infections, but not septic infections. Although the number of S. marcescens cells in hemolymph after oral infection, which were originated from gut-colonizing S. marcescens, was higher than the fatal number of cells used in septic injection, they did not kill host insects, suggesting a loss of virulence in gut-colonizing S. marcescens cells. When gut-colonizing S. marcescens cells were septically injected into insects, they failed to kill R. pedestris and survive in hemolymph. To understand the avirulence mechanisms in gut-colonizing bacteria, lipopolysaccharides of S. marcescens were analyzed and revealed that the O antigen was lost during gut colonization. Gut-colonizing S. marcescens cells were resistant to humoral immune responses but susceptible to cellular immune responses, easily succumbing to phagocytosis of hemocytes. When cellular immunity was suppressed, the gut-colonizing S. marcescens cells recovered their virulence and killed insects through septic injection. These results suggest that a key mechanism of avirulence in orally infected S. marcescens is the loss of the O antigen, resulting in susceptibility to host's cellular immune responses.
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Affiliation(s)
- Junbeom Lee
- Metabolomics Research Center for Functional Materials, Kyungsung University, Busan, Republic of Korea
| | - Jong Uk Kim
- Host Defense Protein Laboratory, College of Pharmacy, Pusan National University, Busan, Republic of Korea
| | - Bok Luel Lee
- Host Defense Protein Laboratory, College of Pharmacy, Pusan National University, Busan, Republic of Korea
| | - Jiyeun Kate Kim
- Department of Microbiology, Kosin University College of Medicine, Busan, Republic of Korea
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Ren Y, Wang Y, Chen J, Fu S, Bu W, Xue H. Integrated analysis of miRNA profiles and gut bacterial changes in Altica viridicyanea following antibiotic treatment. Ecol Evol 2023; 13:e10660. [PMID: 37915809 PMCID: PMC10616750 DOI: 10.1002/ece3.10660] [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] [Received: 05/11/2023] [Revised: 09/29/2023] [Accepted: 10/12/2023] [Indexed: 11/03/2023] Open
Abstract
The gut bacteria involves in insect homeostasis by playing essential roles in host physiology, metabolism, innate immunity, and so forth. microRNAs (miRNAs) are endogenous small noncoding RNAs that posttranscriptionally regulate gene expression to affect immune or metabolic processes in insects. For several non-model insects, the available knowledge on the relationship between changes in the gut bacteria and miRNA profiles is limited. In this study, we investigated the gut bacterial diversity, composition, and function from Altica viridicyanea feeding on normal- and antibiotic-treated host plants using 16S rRNA amplicon sequencing; antibiotics have been shown to affect the body weight and development time in A. viridicyanea, suggesting that the gut bacteria of the normal sample were more diverse and abundant than those of the antibiotic-fed group, and most of them were involved in various physical functions by enrichment analysis. Furthermore, we executed small RNA transcriptome sequencing using the two experimental groups to obtain numerous sRNAs, such as piRNAs, siRNAs, and known and novel miRNAs, by data mapping and quality control, and furthermore, a total of 224 miRNAs were identified as significantly differentially expressed miRNAs, of which some DEMs and their target genes participated in immune- and metabolism-related pathways based on GO and KEGG annotation. Besides, regarding the regulatory roles of miRNA and target genes, a interaction network of DEM-target gene pairs from eight immune- or metabolism-related signaling pathways were constructed. Finally, we discovered that DEMs from above pathways were significantly positively or negatively correlated with gut bacterial alterations following antibiotic treatment. Collectively, the observations of this study expand our understanding of how the disturbance of gut bacteria affects miRNA profiles in A. viridicyanea and provide new valuable resources from extreme ranges for future studies on the adaptive evolution in insects.
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Affiliation(s)
- Yipeng Ren
- Institute of Entomology, College of Life SciencesNankai UniversityTianjinChina
| | - Yuan Wang
- Institute of Entomology, College of Life SciencesNankai UniversityTianjinChina
| | - Juhong Chen
- Institute of Entomology, College of Life SciencesNankai UniversityTianjinChina
| | - Siying Fu
- Institute of Entomology, College of Life SciencesNankai UniversityTianjinChina
| | - Wenjun Bu
- Institute of Entomology, College of Life SciencesNankai UniversityTianjinChina
| | - Huaijun Xue
- Institute of Entomology, College of Life SciencesNankai UniversityTianjinChina
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Ren Y, Chen J, Wang Y, Fu S, Bu W, Xue H. The lncRNA-mediated ceRNA network of Altica viridicyanea is involved in the regulation of the Toll/Imd signaling pathway under antibiotic treatment. Front Physiol 2023; 14:1244190. [PMID: 37664435 PMCID: PMC10470016 DOI: 10.3389/fphys.2023.1244190] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 08/02/2023] [Indexed: 09/05/2023] Open
Abstract
Long noncoding RNAs (lncRNAs) play significant roles in the regulation of mRNA expression or in shaping the competing endogenous RNA (ceRNA) network by targeting miRNA. The insect gut is one of the most important tissues due to direct contact with external pathogens and functions in the immune defense against pathogen infection through the innate immune system and symbionts, but there are limited observations on the role of the lncRNA-involved ceRNA network of the Toll/Imd pathway and correlation analysis between this network and bacterial microbiota in the Altica viridicyanea gut. In this research, we constructed and sequenced six RNA sequencing libraries using normal and antibiotic-reared samples, generating a total of 17,193 lncRNAs and 26,361 mRNAs from massive clean data by quality control and bioinformatic analysis. Furthermore, a set of 8,539 differentially expressed lncRNAs (DELs) and 13,263 differentially expressed mRNAs (DEMs), of which related to various immune signaling pathways, such as the Toll/Imd, JAK/STAT, NF-κB, and PI3K-Akt signaling pathways, were obtained between the two experimental groups in A. viridicyanea. In addition, numerous GO and KEGG enrichment analyses were used to annotate the DELs and their target genes. Moreover, six Toll family members and nineteen signal genes from the Toll/Imd signaling pathway were identified and characterized using online tools, and phylogenetic analyses of the above genes proved their classification. Next, a lncRNA-miRNA-mRNA network of the Toll/Imd pathway was built, and it contained different numbers of DEMs in this pathway and related DELs based on prediction and annotation. In addition, qRT-PCR validation and sequencing data were conducted to show the expression patterns of the above DELs and DEMs related to the Toll/Imd signaling pathway. Finally, the correlated investigations between DELs or DEMs of the Toll/Imd signaling pathway and most changes in the gut bacterial microbiota revealed significantly positive or negative relationships between them. The present findings provide essential evidence for innate immune ceRNAs in the beetle gut and uncover new potential relationships between innate immune pathways and the gut bacterial microbiota in insects.
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Affiliation(s)
| | | | | | | | - Wenjun Bu
- Institute of Entomology, College of Life Sciences, Nankai University, Tianjin, China
| | - Huaijun Xue
- Institute of Entomology, College of Life Sciences, Nankai University, Tianjin, China
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Unraveling the Role of Antimicrobial Peptides in Insects. Int J Mol Sci 2023; 24:ijms24065753. [PMID: 36982826 PMCID: PMC10059942 DOI: 10.3390/ijms24065753] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 03/14/2023] [Accepted: 03/15/2023] [Indexed: 03/19/2023] Open
Abstract
Antimicrobial peptides (AMPs) are short, mainly positively charged, amphipathic molecules. AMPs are important effectors of the immune response in insects with a broad spectrum of antibacterial, antifungal, and antiparasitic activity. In addition to these well-known roles, AMPs exhibit many other, often unobvious, functions in the host. They support insects in the elimination of viral infections. AMPs participate in the regulation of brain-controlled processes, e.g., sleep and non-associative learning. By influencing neuronal health, communication, and activity, they can affect the functioning of the insect nervous system. Expansion of the AMP repertoire and loss of their specificity is connected with the aging process and lifespan of insects. Moreover, AMPs take part in maintaining gut homeostasis, regulating the number of endosymbionts as well as reducing the number of foreign microbiota. In turn, the presence of AMPs in insect venom prevents the spread of infection in social insects, where the prey may be a source of pathogens.
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11
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Lee J, Lee DW. Burkholderia gut symbiont induces insect host fecundity by modulating Kr-h1 gene expression. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2023; 112:e21987. [PMID: 36448663 DOI: 10.1002/arch.21987] [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: 11/21/2022] [Accepted: 11/22/2022] [Indexed: 06/17/2023]
Abstract
Full-length cDNAs of the Broad-Complex (BR-C) from Riptortus pedestris were cloned. Moreover, Kr-h1 and BR-C expression levels in apo-symbiotic and symbiotic host insects were compared to verify whether they are modulated by Burkholderia gut symbionts. Interestingly, Kr-h1 expression level was significantly increased in symbiotic females. To determine how Kr-h1 affects fecundity in insects, the biosynthesis of two reproduction-associated proteins, hexamerin-α and vitellogenin, was investigated in R. pedestris females. Hexamerin-α and vitellogenin expression at the transcriptional and translational levels decreased in Kr-h1-suppressed symbiotic females, subsequently reduced egg production. These results suggest that Burkholderia gut symbiont modulates Kr-h1 expression to enhance ovarian development and egg production of R. pedestris by increasing the biosynthesis of the two proteins.
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Affiliation(s)
- Junbeom Lee
- Metabolomics Research Center for Functional Materials, Kyungsung University, Busan, Republic of Korea
| | - Dae-Weon Lee
- Metabolomics Research Center for Functional Materials, Kyungsung University, Busan, Republic of Korea
- Department of SmartBio, Kyungsung University, Busan, Republic of Korea
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Lee J, Lee DW. Insecticidal Serralysin of Serratia marcescens Is Detoxified in M3 Midgut Region of Riptortus pedestris. Front Microbiol 2022; 13:913113. [PMID: 35711769 PMCID: PMC9197470 DOI: 10.3389/fmicb.2022.913113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 05/06/2022] [Indexed: 11/18/2022] Open
Abstract
Riptortus pedestris insect indiscriminately acquires not only the symbiotic bacterium Burkholderia insecticola, but also entomopathogens that are abundant in the soil via feeding. However, it is unclear how the host insect survives oral infections of entomopathogens. A previous study suggested that serralysin, a potent virulence factor produced by Serratia marcescens, suppresses cellular immunity by degrading adhesion molecules, thereby contributing to bacterial pathogenesis. Here, we observed that S. marcescens orally administered to R. pedestris stably colonized the insect midgut, while not exhibiting insecticidal activity. Additionally, oral infection with S. marcescens did not affect the host growth or fitness. When co-incubated with the midgut lysates of R. pedestris, serralysin was remarkably degraded. The detoxification activity against serralysin was enhanced in the midgut extract of gut symbiont-colonizing insects. The mRNA expression levels of serralysin genes were negligible in M3-colonizing S. marcescens. M3-colonizing S. marcescens did not produce serralysin toxin. Immunoblot analyses revealed that serralysin was not detected in the M3 midgut region. The findings of our study suggest that orally infected S. marcescens lose entomopathogenicity through host-derived degrading factors and suppression of serralysin.
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Affiliation(s)
- Junbeom Lee
- Metabolomics Research Center for Functional Materials, Kyungsung University, Busan, South Korea
| | - Dae-Weon Lee
- Metabolomics Research Center for Functional Materials, Kyungsung University, Busan, South Korea.,Department of SmartBio, Kyungsung University, Busan, South Korea
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