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Rami M, Shafique M, Sarma SP. Structural, Functional, and Mutational Studies of a Potent Subtilisin Inhibitor from Budgett's Frog, Lepidobatrachus laevis. Biochemistry 2023; 62:2952-2969. [PMID: 37796763 DOI: 10.1021/acs.biochem.3c00252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/07/2023]
Abstract
Subtilases play a significant role in microbial pathogen infections by degrading the host proteins. Subtilisin inhibitors are crucial in fighting against these harmful microorganisms. LL-TIL, from skin secretions of Lepidobatrachus laevis, is a cysteine-rich peptide belonging to the I8 family of inhibitors. Protease inhibitory assays demonstrated that LL-TIL acts as a slow-tight binding inhibitor of subtilisin Carlsberg and proteinase K with inhibition constants of 91 pM and 2.4 nM, respectively. The solution structures of LL-TIL and a mutant peptide reveal that they adopt a typical TIL-type fold with a canonical conformation of a reactive site loop (RSL). The structure of the LL-TIL-subtilisin complex and molecular dynamics (MD) simulations provided an in-depth view of the structural basis of inhibition. NMR relaxation data and molecular dynamics simulations indicated a rigid conformation of RSL, which does not alter significantly upon subtilisin binding. The energy calculation for subtilisin inhibition predicted Ile31 as the highest contributor to the binding energy, which was confirmed experimentally by site-directed mutagenesis. A chimeric mutant of LL-TIL broadened the inhibitory profile and attenuated subtilisin inhibition by 2 orders of magnitude. These results provide a template to engineer more specific and potent TIL-type subtilisin inhibitors.
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Affiliation(s)
- Mihir Rami
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Mohd Shafique
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Siddhartha P Sarma
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka 560012, India
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Tikhe CV, Cardoso-Jaime V, Dong S, Rutkowski N, Dimopoulos G. Trypsin-like Inhibitor Domain (TIL)-Harboring Protein Is Essential for Aedes aegypti Reproduction. Int J Mol Sci 2022; 23:ijms23147736. [PMID: 35887084 PMCID: PMC9319116 DOI: 10.3390/ijms23147736] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 07/04/2022] [Accepted: 07/05/2022] [Indexed: 02/06/2023] Open
Abstract
Cysteine-rich trypsin inhibitor-like domain (TIL)-harboring proteins are broadly distributed in nature but remain understudied in vector mosquitoes. Here we have explored the biology of a TIL domain-containing protein of the arbovirus vector Aedes aegypti, cysteine-rich venom protein 379 (CRVP379). CRVP379 was previously shown to be essential for dengue virus infection in Ae. aegypti mosquitoes. Gene expression analysis showed CRVP379 to be highly expressed in pupal stages, male testes, and female ovaries. CRVP379 expression is also increased in the ovaries at 48 h post-blood feeding. We used CRISPR-Cas9 genome editing to generate two mutant lines of CRVP379 with mutations inside or outside the TIL domain. Female mosquitoes from both mutant lines showed severe defects in their reproductive capability; mutant females also showed differences in their follicular cell morphology. However, the CRVP379 line with a mutation outside the TIL domain did not affect male reproductive performance, suggesting that some CRVP379 residues may have sexually dimorphic functions. In contrast to previous reports, we did not observe a noticeable difference in dengue virus infection between the wild-type and any of the mutant lines. The importance of CRVP379 in Ae. aegypti reproductive biology makes it an interesting candidate for the development of Ae. aegypti population control methods.
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Affiliation(s)
- Chinmay Vijay Tikhe
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA; (C.V.T.); (V.C.-J.); (S.D.); (N.R.)
- Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Victor Cardoso-Jaime
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA; (C.V.T.); (V.C.-J.); (S.D.); (N.R.)
- Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Shengzhang Dong
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA; (C.V.T.); (V.C.-J.); (S.D.); (N.R.)
- Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Natalie Rutkowski
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA; (C.V.T.); (V.C.-J.); (S.D.); (N.R.)
- Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - George Dimopoulos
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA; (C.V.T.); (V.C.-J.); (S.D.); (N.R.)
- Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
- Correspondence:
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Martins LA, Malossi CD, Galletti MFBDM, Ribeiro JM, Fujita A, Esteves E, Costa FB, Labruna MB, Daffre S, Fogaça AC. The Transcriptome of the Salivary Glands of Amblyomma aureolatum Reveals the Antimicrobial Peptide Microplusin as an Important Factor for the Tick Protection Against Rickettsia rickettsii Infection. Front Physiol 2019; 10:529. [PMID: 31130872 PMCID: PMC6509419 DOI: 10.3389/fphys.2019.00529] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 04/12/2019] [Indexed: 11/17/2022] Open
Abstract
The salivary glands (SG) of ixodid ticks play a pivotal role in blood feeding, producing both the cement and the saliva. The cement is an adhesive substance that helps the attachment of the tick to the host skin, while the saliva contains a rich mixture of antihemostatic, anti-inflammatory, and immunomodulatory substances that allow ticks to properly acquire the blood meal. The tick saliva is also a vehicle used by several pathogens to be transmitted to the vertebrate host, including various bacterial species from the genus Rickettsia. Rickettsia rickettsii is a tick-borne obligate intracellular bacterium that causes the severe Rocky Mountain spotted fever. In Brazil, the dog yellow tick Amblyomma aureolatum is a vector of R. rickettsii. In the current study, the effects of an experimental infection with R. rickettsii on the global gene expression profile of A. aureolatum SG was determined by next-generation RNA sequencing. A total of 260 coding sequences (CDSs) were modulated by infection, among which 161 were upregulated and 99 were downregulated. Regarding CDSs in the immunity category, we highlight one sequence encoding one microplusin-like antimicrobial peptide (AMP) (Ambaur-69859). AMPs are important effectors of the arthropod immune system, which lack the adaptive response of the immune system of vertebrates. The expression of microplusin was confirmed to be significantly upregulated in the SG as well as in the midgut (MG) of infected A. aureolatum by a quantitative polymerase chain reaction preceded by reverse transcription. The knockdown of the microplusin expression by RNA interference caused a significant increase in the prevalence of infected ticks in relation to the control. In addition, a higher rickettsial load of one order of magnitude was recorded in both the MG and SG of ticks that received microplusin-specific dsRNA. No effect of microplusin knockdown was observed on the R. rickettsii transmission to rabbits. Moreover, no significant differences in tick engorgement and oviposition were recorded in ticks that received dsMicroplusin, demonstrating that microplusin knockdown has no effect on tick fitness. Further studies must be performed to determine the mechanism of action of this AMP against R. rickettsii.
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Affiliation(s)
- Larissa A Martins
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Camila D Malossi
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Maria F B de M Galletti
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - José M Ribeiro
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, Bethesda, MD, United States
| | - André Fujita
- Departamento de Ciência da Computação, Instituto de Matemática e Estatística, Universidade de São Paulo, São Paulo, Brazil
| | - Eliane Esteves
- Departamento de Imunologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Francisco B Costa
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, Brazil
| | - Marcelo B Labruna
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, Brazil
| | - Sirlei Daffre
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Andréa C Fogaça
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
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Esteves E, Maruyama SR, Kawahara R, Fujita A, Martins LA, Righi AA, Costa FB, Palmisano G, Labruna MB, Sá-Nunes A, Ribeiro JMC, Fogaça AC. Analysis of the Salivary Gland Transcriptome of Unfed and Partially Fed Amblyomma sculptum Ticks and Descriptive Proteome of the Saliva. Front Cell Infect Microbiol 2017; 7:476. [PMID: 29209593 PMCID: PMC5702332 DOI: 10.3389/fcimb.2017.00476] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 10/31/2017] [Indexed: 12/22/2022] Open
Abstract
Ticks are obligate blood feeding ectoparasites that transmit a wide variety of pathogenic microorganisms to their vertebrate hosts. Amblyomma sculptum is vector of Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever (RMSF), the most lethal rickettsiosis that affects humans. It is known that the transmission of pathogens by ticks is mainly associated with the physiology of the feeding process. Pathogens that are acquired with the blood meal must first colonize the tick gut and later the salivary glands (SG) in order to be transmitted during a subsequent blood feeding via saliva. Tick saliva contains a complex mixture of bioactive molecules with anticlotting, antiplatelet aggregation, vasodilatory, anti-inflammatory, and immunomodulatory properties to counteract both the hemostasis and defense mechanisms of the host. Besides facilitating tick feeding, the properties of saliva may also benefits survival and establishment of pathogens in the host. In the current study, we compared the sialotranscriptome of unfed A. sculptum ticks and those fed for 72 h on rabbits using next generation RNA sequencing (RNA-seq). The total of reads obtained were assembled in 9,560 coding sequences (CDSs) distributed in different functional classes. CDSs encoding secreted proteins, including lipocalins, mucins, protease inhibitors, glycine-rich proteins, metalloproteases, 8.9 kDa superfamily members, and immunity-related proteins were mostly upregulated by blood feeding. Selected CDSs were analyzed by real-time quantitative polymerase chain reaction preceded by reverse transcription (RT-qPCR), corroborating the transcriptional profile obtained by RNA-seq. Finally, high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) analysis revealed 124 proteins in saliva of ticks fed for 96–120 h. The corresponding CDSs of 59 of these proteins were upregulated in SG of fed ticks. To the best of our knowledge, this is the first report on the proteome of A. sculptum saliva. The functional characterization of the identified proteins might reveal potential targets to develop vaccines for tick control and/or blocking of R. rickettsii transmission as well as pharmacological bioproducts with antihemostatic, anti-inflammatory and antibacterial activities.
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Affiliation(s)
- Eliane Esteves
- Departamento de Imunologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Sandra R Maruyama
- Departamento de Genética e Evolução, Universidade Federal de São Carlos, São Carlos, Brazil
| | - Rebeca Kawahara
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - André Fujita
- Departamento de Ciência da Computação, Instituto de Matemática e Estatística, Universidade de São Paulo, São Paulo, Brazil
| | - Larissa A Martins
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Adne A Righi
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Francisco B Costa
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, Brazil
| | - Giuseppe Palmisano
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Marcelo B Labruna
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia, Universidade de São Paulo, São Paulo, Brazil
| | - Anderson Sá-Nunes
- Departamento de Imunologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - José M C Ribeiro
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, Bethesda, MD, United States
| | - Andréa C Fogaça
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
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