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Kitsou C, Pal U. Ixodes Immune Responses Against Lyme Disease Pathogens. Front Cell Infect Microbiol 2018; 8:176. [PMID: 29896452 PMCID: PMC5986905 DOI: 10.3389/fcimb.2018.00176] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 05/08/2018] [Indexed: 12/15/2022] Open
Abstract
Although Ixodes scapularis and other related tick species are considered prolific vectors for a number of important human diseases, many aspects of their biology, microbial interactions, and immunity are largely unknown; in particular, how these ancient vectors recognize invading pathogens like Borrelia burgdorferi and influence their persistence. The analysis of the Ixodes genome and a limited set of transcriptomic data have established that ticks encode many components of classical immune pathways; yet at the same time, they lack many key orthologs of these recognition networks. Therefore, whether a given immune pathway is active in Ixodes ticks and how precisely they exert its microbicidal functions are only incompletely delineated. A few recent studies have suggested that classical pathways like the Janus Kinase/Signal Transducer and Activator of Transcription (JAK/STAT) as well as immunodeficiency (IMD) pathways are fully functional in I. scapularis, and upon challenge with microbes, generate potent microbicidal responses against diverse tick-borne pathogens including B. burgdorferi. These studies also highlight novel concepts of vector immunity that include both a direct and an indirect mode of recognition of pathogens, as well as the influence of the gut microbiome, which ultimately dictates the outcome of a robust microbicidal response. Further understanding of how Ixodes ticks recognize and suppress invading microbes like B. burgdorferi will enrich our fundamental knowledge of vector immunobiology, thereby contributing to the development of future interventions to better control the tick-borne pathogen.
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Affiliation(s)
- Chrysoula Kitsou
- Department of Veterinary Medicine and Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD, United States
| | - Utpal Pal
- Department of Veterinary Medicine and Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD, United States
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The Silencing of a 14-3-3ɛ Homolog in Tenebrio molitor Leads to Increased Antimicrobial Activity in Hemocyte and Reduces Larval Survivability. Genes (Basel) 2016; 7:genes7080053. [PMID: 27556493 PMCID: PMC4999841 DOI: 10.3390/genes7080053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 08/16/2016] [Accepted: 08/17/2016] [Indexed: 11/22/2022] Open
Abstract
The 14-3-3 family of phosphorylated serine-binding proteins acts as signaling molecules in biological processes such as metabolism, division, differentiation, autophagy, and apoptosis. Herein, we report the requirement of 14-3-3ɛ isoform from Tenebrio molitor (Tm14-3-3ɛ) in the hemocyte antimicrobial activity. The Tm14-3-3ɛ transcript is 771 nucleotides in length and encodes a polypeptide of 256 amino acid residues. The protein has the typical 14-3-3 domain, the nuclear export signal (NES) sequence, and the peptide binding residues. The Tm14-3-3ɛ transcript shows a significant three-fold expression in the hemocyte of T. molitor larvae when infected with Escherichia coliTm14-3-3ɛ silenced larvae show significantly lower survival rates when infected with E. coli. Under Tm14-3-3ɛ silenced condition, a strong antimicrobial activity is elicited in the hemocyte of the host inoculated with E. coli. This suggests impaired secretion of antimicrobial peptides (AMP) into the hemolymph. Furthermore, a reduction in AMP secretion under Tm14-3-3ɛ silenced condition would be responsible for loss in the capacity to kill bacteria and might explain the reduced survivability of the larvae upon E. coli challenge. This shows that Tm14-3-3ɛ is required to maintain innate immunity in T. molitor by enabling antimicrobial secretion into the hemolymph and explains the functional specialization of the isoform.
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Smith AA, Navasa N, Yang X, Wilder CN, Buyuktanir O, Marques A, Anguita J, Pal U. Cross-Species Interferon Signaling Boosts Microbicidal Activity within the Tick Vector. Cell Host Microbe 2016; 20:91-8. [PMID: 27374407 DOI: 10.1016/j.chom.2016.06.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 04/13/2016] [Accepted: 05/30/2016] [Indexed: 12/20/2022]
Abstract
Evolution of hematophagy in blood-sucking parasites likely involves communication with their hosts. We find that Ixodes ticks are responsive to IFNγ acquired in a blood meal from mice infected with the Lyme disease-causing bacteria Borrelia burgdorferi, leading to induction of antimicrobial responses. Ixodes ticks parasitizing B. burgdorferi-infected mice upregulated an I. scapularis Rho-like GTPase (IGTPase). IGTPase knockdown enhanced B. burgdorferi levels in post-fed ticks, suggesting this protein controls spirochete survival. Notably, IGTPase was only induced during pathogen acquisition from mice and not upon transmission to naive hosts. Microinjection of ticks with IFNγ induced IGTPase, and ticks parasitizing IFNγ knockout mice, failed to upregulate IGTPase. Additionally, ticks lacking the transcription factor STAT, which signals downstream of IFNγ, did not induce IGTPase. IGTPase expression induced antimicrobial peptides, including Dae2, previously shown to inhibit B. burgdorferi. These results identify an interspecies signaling cascade allowing ticks to detect invading bacteria and mount microbicidal responses.
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Affiliation(s)
- Alexis A Smith
- Department of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA
| | | | - Xiuli Yang
- Department of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA
| | - Cara N Wilder
- Department of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA
| | - Ozlem Buyuktanir
- Department of Microbiology, Faculty of Veterinary Medicine, Ondokuz Mayis University, Samsun 55139, Turkey
| | - Adriana Marques
- Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892, USA
| | - Juan Anguita
- CIC bioGUNE, 48160 Derio, Bizkaia, Spain; Ikerbasque, Basque Foundation for Science, 48011 Bilbao, Bizkaia, Spain
| | - Utpal Pal
- Department of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA; Virginia-Maryland Regional College of Veterinary Medicine, College Park, MD 20742, USA.
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Bombyx mori cecropin A has a high antifungal activity to entomopathogenic fungus Beauveria bassiana. Gene 2016; 583:29-35. [DOI: 10.1016/j.gene.2016.02.045] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/26/2016] [Accepted: 02/28/2016] [Indexed: 11/18/2022]
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Xia L, Liu Z, Ma J, Sun S, Yang J, Zhang F. Expression, purification and characterization of cecropin antibacterial peptide from Bombyx mori in Saccharomyces cerevisiae. Protein Expr Purif 2013; 90:47-54. [PMID: 23500722 DOI: 10.1016/j.pep.2013.02.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 02/19/2013] [Accepted: 02/20/2013] [Indexed: 01/14/2023]
Abstract
CecropinXJ is a cationic antimicrobial peptide originally isolated from the larvae of Bombyx mori. In this study, an antibacterial peptide gene of cecropinXJ was cloned into the pYES2/CT/α Factor expression vector and expressed in the Saccharomyces cerevisiae INVSc1 strain. Following an induction of recombinant protein expression in yeast for 120 h, the maximum amount of total secreted protein was 1.437 g/L. The percentage of recombinant cecropinXJ was estimated to be 79.45% of the total protein. After purification with Ni-NTA agarose column, recombinant cecropinXJ was noted to exert strong antimicrobial activities against a broad-spectrum of microorganisms, including Gram-negative and Gram-positive bacteria. Its minimal inhibitory concentration (MIC) against Escherichia coli ATCC25922 was 0.81 μM. In addition, transmission electron microscopy (TEM) analysis indicated that the surfaces of the treated pathogens underwent obvious morphological changes compared with the untreated controls, suggesting that this antimicrobial peptide exerts its action by directly disrupting membranes of microorganisms. CecropinXJ had a small hemolytic effect on red blood cells even with a peptide concentration of 200 μM. Thus, cecropinXJ acts selectively on bacterial membranes. Purified recombinant antibacterial peptide, cecropinXJ, retained a high stability against E. coli ATCC25922 over a temperature range from 4 °C to 100 °C and a pH range from pH 2.0 to 12.0. Taken together, this study demonstrates that recombinant cecropinXJ can be produced in large quantities in yeast with genetic engineering methods, and that it has strong and rapid antimicrobial activities against all of microorganisms tested. Our results suggest that cecropinXJ is a potential candidate for therapy.
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Affiliation(s)
- Lijie Xia
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830046, PR China
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