1
|
Ouyang X, Reihill JA, Douglas LEJ, Martin SL. Airborne indoor allergen serine proteases and their contribution to sensitisation and activation of innate immunity in allergic airway disease. Eur Respir Rev 2024; 33:230126. [PMID: 38657996 PMCID: PMC11040391 DOI: 10.1183/16000617.0126-2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 02/28/2024] [Indexed: 04/26/2024] Open
Abstract
Common airborne allergens (pollen, animal dander and those from fungi and insects) are the main triggers of type I allergic disorder in the respiratory system and are associated with allergic rhinitis, allergic asthma, as well as immunoglobulin E (IgE)-mediated allergic bronchopulmonary aspergillosis. These allergens promote IgE crosslinking, vasodilation, infiltration of inflammatory cells, mucosal barrier dysfunction, extracellular matrix deposition and smooth muscle spasm, which collectively cause remodelling of the airways. Fungus and insect (house dust mite and cockroaches) indoor allergens are particularly rich in proteases. Indeed, more than 40 different types of aeroallergen proteases, which have both IgE-neutralising and tissue-destructive activities, have been documented in the Allergen Nomenclature database. Of all the inhaled protease allergens, 85% are classed as serine protease activities and include trypsin-like, chymotrypsin-like and collagenolytic serine proteases. In this article, we review and compare the allergenicity and proteolytic effect of allergen serine proteases as listed in the Allergen Nomenclature and MEROPS databases and highlight their contribution to allergic sensitisation, disruption of the epithelial barrier and activation of innate immunity in allergic airways disease. The utility of small-molecule inhibitors of allergen serine proteases as a potential treatment strategy for allergic airways disease will also be discussed.
Collapse
Affiliation(s)
- Xuan Ouyang
- School of Pharmacy, Queen's University Belfast, Belfast, UK
| | | | | | | |
Collapse
|
2
|
Parekh AB. House dust mite allergens, store-operated Ca 2+ channels and asthma. J Physiol 2023. [PMID: 38054814 DOI: 10.1113/jp284931] [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: 08/11/2023] [Accepted: 10/26/2023] [Indexed: 12/07/2023] Open
Abstract
The house dust mite is the principal source of aero-allergen worldwide. Exposure to mite-derived allergens is associated with the development of asthma in susceptible individuals, and the majority of asthmatics are allergic to the mite. Mite-derived allergens are functionally diverse and activate multiple cell types within the lung that result in chronic inflammation. Allergens activate store-operated Ca2+ release-activated Ca2+ (CRAC) channels, which are widely expressed in multiple cell types within the lung that are associated with the pathogenesis of asthma. Opening of CRAC channels stimulates Ca2+ -dependent transcription factors, including nuclear factor of activated T cells and nuclear factor-κB, which drive expression of a plethora of pro-inflammatory cytokines and chemokines that help to sustain chronic inflammation. Here, I describe drivers of asthma, properties of mite-derived allergens, how the allergens are recognized by cells, the signalling pathways used by the receptors and how these are transduced into functional effects, with a focus on CRAC channels. In vivo experiments that demonstrate the effectiveness of targeting CRAC channels as a potential new therapy for treating mite-induced asthma are also discussed, in tandem with other possible approaches.
Collapse
Affiliation(s)
- Anant B Parekh
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, US National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| |
Collapse
|
3
|
Ragweed Major Allergen Amb a 11 Recombinant Production and Clinical Implications. Biomolecules 2023; 13:biom13010182. [PMID: 36671567 PMCID: PMC9855870 DOI: 10.3390/biom13010182] [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: 12/12/2022] [Revised: 01/09/2023] [Accepted: 01/12/2023] [Indexed: 01/17/2023] Open
Abstract
Ragweed pollen is highly allergenic and elicits type I hypersensitivity reactions in the exposed populations. Amb a 11 is a recently discovered component of this pollen, and its biological role in allergy is still being researched. In our study, ragweed allergy patients were recruited prospectively over a three-year period; a comprehensive questionnaire was administered, and sera were collected and stored. The production of recombinant Amb a 11 was achieved in parallel with patients' recruitment. The gene coding for mature protein was inserted in E. coli and in Sf9 Spodoptera frugiperda cells. The recombinant allergens (designated eAmb a 11 and iAmb a 11) were tested for His-tag presence in Western blot. IgE reactivity was evaluated in 150 patients' sera for both recombinant allergen forms in ELISA, with 5 positive sera being tested further by hRBL (humanized rat basophilic leukemia) hexosaminidase release assay. Both allergen forms were proven to be IgE-reactive His-tagged proteins, with an extensive overlap of positive sera (92 toward the former recombinant allergen, 100 toward the latter) and an overall Amb a 11 sensitization prevalence estimated at 68.67%. The hRBL mediator release assay revealed a significant, slightly weaker effect of recombinant allergens when compared with nAmb a 1. Sensitization to this major allergen appears to be associated with more severe asthma symptoms (OR = 4.71, 95% CI = 1.81-12.21). In conclusion, recombinant Amb a 11 is a bona fide allergen, which is IgE-reactive and an inducer of hRBL degranulation. It is an important IgE-reactive component from ragweed pollen, with high IgE sensitization prevalence in the sample population and allergenicity of the recombinant allergen comparable to Amb a 1.
Collapse
|
4
|
Abstract
The house dust mite (HDM) is globally ubiquitous in human habitats. Thirty-two allergens for Dermatophagoides farinae and 21 for Dermatophagoides pteronyssinus have been detected so far. The present minireview summarizes information about the role of Der p 1 as a key coordinator of the HDM-induced allergic response and reports on a series of Italian patients who are allergic to HDMs. We studied the specific IgE profiles in a population of patients with allergic asthma and rhinitis screened for specific immunotherapy (SIT) for HDM allergies, with the aim of obtaining insights into the pathogenic role of Der p1. Patients co-sensitized to other airborne allergens showed a higher prevalence of asthma (9/12 (75%) vs. 2/7 (29%); p < 0.05) than did HDM mono-sensitized patients. The latter group showed higher Der p1 concentrations than that of the co-sensitized group (p = 0.0360), and a direct correlation between Der p1 and Der p2 (r = 0.93; p = 0.0003) was observed. In conclusion, our study offers insights into the role of Der p1 in a population of patients with allergic rhinitis and asthma who were candidates for SIT. Interestingly, Der p1 positivity was associated with bronchial asthma and co-sensitization.
Collapse
|
5
|
Oncofetal Chondroitin Sulfate: A Putative Therapeutic Target in Adult and Pediatric Solid Tumors. Cells 2020; 9:cells9040818. [PMID: 32231047 PMCID: PMC7226838 DOI: 10.3390/cells9040818] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 03/19/2020] [Accepted: 03/26/2020] [Indexed: 12/14/2022] Open
Abstract
Solid tumors remain a major challenge for targeted therapeutic intervention strategies such as antibody-drug conjugates and immunotherapy. At a minimum, clear and actionable solid tumor targets have to comply with the key biological requirement of being differentially over-expressed in solid tumors and metastasis, in contrast to healthy organs. Oncofetal chondroitin sulfate is a cancer-specific secondary glycosaminoglycan modification to proteoglycans expressed in a variety of solid tumors and metastasis. Normally, this modification is found to be exclusively expressed in the placenta, where it is thought to facilitate normal placental implantation during pregnancy. Informed by this biology, oncofetal chondroitin sulfate is currently under investigation as a broad and specific target in solid tumors. Here, we discuss oncofetal chondroitin sulfate as a potential therapeutic target in childhood solid tumors in the context of current knowhow obtained over the past five years in adult cancers.
Collapse
|
6
|
Lin YP, Nelson C, Kramer H, Parekh AB. The Allergen Der p3 from House Dust Mite Stimulates Store-Operated Ca 2+ Channels and Mast Cell Migration through PAR4 Receptors. Mol Cell 2019; 70:228-241.e5. [PMID: 29677491 DOI: 10.1016/j.molcel.2018.03.025] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 02/05/2018] [Accepted: 03/22/2018] [Indexed: 11/17/2022]
Abstract
The house dust mite is the principal source of perennial aeroallergens in man. How these allergens activate innate and adaptive immunity is unclear, and therefore, there are no therapies targeting mite allergens. Here, we show that house dust mite extract activates store-operated Ca2+ channels, a common signaling module in numerous cell types in the lung. Activation of channel pore-forming Orai1 subunits by mite extract requires gating by STIM1 proteins. Although mite extract stimulates both protease-activated receptor type 2 (PAR2) and PAR4 receptors, Ca2+ influx is more tightly coupled to the PAR4 pathway. We identify a major role for the serine protease allergen Der p3 in stimulating Orai1 channels and show that a therapy involving sub-maximal inhibition of both Der p3 and Orai1 channels suppresses mast cell activation to house dust mite. Our results reveal Der p3 as an important aeroallergen that activates Ca2+ channels and suggest a therapeutic strategy for treating mite-induced asthma.
Collapse
Affiliation(s)
- Yu-Ping Lin
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, UK
| | - Charmaine Nelson
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, UK
| | - Holger Kramer
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, UK
| | - Anant B Parekh
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, UK.
| |
Collapse
|
7
|
Abstract
Proteomics encompasses a variety of approaches unraveling both the structural features, post-translational modifications, and abundance of proteins. As of today, proteomic studies have shed light on the primary structure of about 850 allergens, enabling the design of microarrays for improved molecular diagnosis. Proteomic methods including mass spectrometry allow as well to investigate protein-protein interactions, thus yielding precise information on critical epitopes on the surface of allergens. Mass spectrometry is now being applied to the unambiguous identification, characterization, and comprehensive quantification of allergens in a variety of matrices, as diverse as food samples and allergen immunotherapy drug products. As such, it represents a method of choice for quality testing of allergen immunotherapy products.
Collapse
|
8
|
Allergens with Protease Activity from House Dust Mites. Int J Mol Sci 2017; 18:ijms18071368. [PMID: 28653989 PMCID: PMC5535861 DOI: 10.3390/ijms18071368] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Revised: 06/13/2017] [Accepted: 06/21/2017] [Indexed: 11/29/2022] Open
Abstract
Globally, house dust mites (HDM) are one of the main sources of allergens causing Type I allergy, which has a high risk of progressing into a severe disabling disease manifestation such as allergic asthma. The strong protease activities of a number of these allergens are thought to be involved in several steps of the pathophysiology of this allergic disease. It has been a common notion that protease activity may be one of the properties that confers allergenicity to proteins. In this review we summarize and discuss the roles of the different HDM proteases in the development of Type I allergy.
Collapse
|
9
|
Jacquet A, Campisi V, Szpakowska M, Dumez ME, Galleni M, Chevigné A. Profiling the Extended Cleavage Specificity of the House Dust Mite Protease Allergens Der p 1, Der p 3 and Der p 6 for the Prediction of New Cell Surface Protein Substrates. Int J Mol Sci 2017; 18:ijms18071373. [PMID: 28654001 PMCID: PMC5535866 DOI: 10.3390/ijms18071373] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 06/16/2017] [Accepted: 06/21/2017] [Indexed: 12/22/2022] Open
Abstract
House dust mite (HDM) protease allergens, through cleavages of critical surface proteins, drastically influence the initiation of the Th2 type immune responses. However, few human protein substrates for HDM proteases have been identified so far, mainly by applying time-consuming target-specific individual studies. Therefore, the identification of substrate repertoires for HDM proteases would represent an unprecedented key step toward a better understanding of the mechanism of HDM allergic response. In this study, phage display screenings using totally or partially randomized nonameric peptide substrate libraries were performed to characterize the extended substrate specificities (P5–P4′) of the HDM proteases Der p 1, Der p 3 and Der p 6. The bioinformatics interface PoPS (Prediction of Protease Specificity) was then applied to define the proteolytic specificity profile of each protease and to predict new protein substrates within the human cell surface proteome, with a special focus on immune receptors. Specificity profiling showed that the nature of residues in P1 but also downstream the cleavage sites (P′ positions) are important for effective cleavages by all three HDM proteases. Strikingly, Der p 1 and Der p 3 display partially overlapping specificities. Analysis with PoPS interface predicted 50 new targets for the HDM proteases, including 21 cell surface receptors whose extracellular domains are potentially cleaved by Der p 1, Der p 3 and/or Der p 6. Twelve protein substrate candidates were confirmed by phage ELISA (enzyme linked immunosorbent assay). This extensive study of the natural protein substrate specificities of the HDM protease allergens unveils new cell surface target receptors for a better understanding on the role of these proteases in the HDM allergic response and paves the way for the design of specific protease inhibitors for future anti-allergic treatments.
Collapse
Affiliation(s)
- Alain Jacquet
- Faculty of Medicine, Division of Research Affairs, Chulalongkorn University, 10330 Bangkok, Thailand.
| | - Vincenzo Campisi
- Department of Infection and Immunity, Luxembourg Institute of Health (LIH), 29, rue Henri Koch, L-4354 Esch-sur-Alzette, Luxembourg.
- Laboratoire des Macromolécules Biologiques, Centre for Protein Engineering (CIP), University of Liège, 4000 Liège, Belgium.
| | - Martyna Szpakowska
- Department of Infection and Immunity, Luxembourg Institute of Health (LIH), 29, rue Henri Koch, L-4354 Esch-sur-Alzette, Luxembourg.
| | - Marie-Eve Dumez
- Department of Infection and Immunity, Luxembourg Institute of Health (LIH), 29, rue Henri Koch, L-4354 Esch-sur-Alzette, Luxembourg.
- Laboratoire des Macromolécules Biologiques, Centre for Protein Engineering (CIP), University of Liège, 4000 Liège, Belgium.
| | - Moreno Galleni
- Laboratoire des Macromolécules Biologiques, Centre for Protein Engineering (CIP), University of Liège, 4000 Liège, Belgium.
| | - Andy Chevigné
- Department of Infection and Immunity, Luxembourg Institute of Health (LIH), 29, rue Henri Koch, L-4354 Esch-sur-Alzette, Luxembourg.
| |
Collapse
|
10
|
Chevigné A, Campizi V, Szpakowska M, Bourry D, Dumez ME, Martins JC, Matagne A, Galleni M, Jacquet A. The Lys-Asp-Tyr Triad within the Mite Allergen Der p 1 Propeptide Is a Critical Structural Element for the pH-Dependent Initiation of the Protease Maturation. Int J Mol Sci 2017; 18:ijms18051087. [PMID: 28531096 PMCID: PMC5454996 DOI: 10.3390/ijms18051087] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 05/10/2017] [Accepted: 05/12/2017] [Indexed: 12/17/2022] Open
Abstract
The major house dust mite allergen, Der p 1, is a papain-like cysteine protease expressed as an inactive precursor, proDer p 1, carrying an N-terminal propeptide with a unique structure. The maturation of the zymogen into an enzymatically-active form of Der p 1 is a multistep autocatalytic process initiated under acidic conditions through conformational changes of the propeptide, leading to the loss of its inhibitory ability and its subsequent gradual cleavage. The aims of this study were to characterize the residues present in the Der p 1 propeptide involved in the initiation of the zymogen maturation process, but also to assess the impact of acidic pH on the propeptide structure, the activity of Der p 1 and the fate of the propeptide. Using various complementary enzymatic and structural approaches, we demonstrated that a structural triad K17p-D51p-Y19p within the N-terminal domain of the propeptide is essential for its stabilization and the sensing of pH changes. Particularly, the protonation of D51p under acidic conditions unfolds the propeptide through disruption of the K17p-D51p salt bridge, reduces its inhibition capacity and unmasks the buried residues K17p and Y19p constituting the first maturation cleavage site of the zymogen. Our results also evidenced that this triad acts in a cooperative manner with other propeptide pH-responsive elements, including residues E56p and E80p, to promote the propeptide unfolding and/or to facilitate its proteolysis. Furthermore, we showed that acidic conditions modify Der p 1 proteolytic specificity and confirmed that the formation of the first intermediate represents the limiting step of the in vitro Der p 1 maturation process. Altogether, our results provide new insights into the early events of the mechanism of proDer p 1 maturation and identify a unique structural triad acting as a stabilizing and a pH-sensing regulatory element.
Collapse
Affiliation(s)
- Andy Chevigné
- Macromolécules Biologiques, Centre for Protein Engineering, University of Liège, B-4000 Liège, Belgium.
- Department of Infection and Immunity, Luxembourg Institute of Health (LIH), L-4354 Esch-sur-Alzette, Luxembourg.
| | - Vincenzo Campizi
- Macromolécules Biologiques, Centre for Protein Engineering, University of Liège, B-4000 Liège, Belgium.
- Department of Infection and Immunity, Luxembourg Institute of Health (LIH), L-4354 Esch-sur-Alzette, Luxembourg.
| | - Martyna Szpakowska
- Department of Infection and Immunity, Luxembourg Institute of Health (LIH), L-4354 Esch-sur-Alzette, Luxembourg.
| | - David Bourry
- NMR and Structure Analysis Unit, Department of Organic Chemistry, Ghent University, B-9000 Ghent, Belgium.
| | - Marie-Eve Dumez
- Macromolécules Biologiques, Centre for Protein Engineering, University of Liège, B-4000 Liège, Belgium.
- Department of Infection and Immunity, Luxembourg Institute of Health (LIH), L-4354 Esch-sur-Alzette, Luxembourg.
| | - José C Martins
- NMR and Structure Analysis Unit, Department of Organic Chemistry, Ghent University, B-9000 Ghent, Belgium.
| | - André Matagne
- Laboratoire d'Enzymologie, Centre for Protein Engineering, University of Liège, B-4000 Liège, Belgium.
| | - Moreno Galleni
- Macromolécules Biologiques, Centre for Protein Engineering, University of Liège, B-4000 Liège, Belgium.
| | - Alain Jacquet
- Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand.
| |
Collapse
|
11
|
Santos da Silva E, Asam C, Lackner P, Hofer H, Wallner M, Silva Pinheiro C, Alcântara-Neves NM, Ferreira F. Allergens of Blomia tropicalis: An Overview of Recombinant Molecules. Int Arch Allergy Immunol 2017; 172:203-214. [PMID: 28456805 PMCID: PMC5472214 DOI: 10.1159/000464325] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Allergic diseases are considered a major problem for healthcare systems in both developed and developing countries. House dust mites are well-known triggers of allergic manifestations. While the Dermatophagoides genus is widely distributed globally, Blomia tropicalis is the most prominent mite species in the tropical and subtropical regions of the world. Over the last decades, an increase in sensitization rates to B. tropicalis has been reported, leading to increased research efforts on Blomia allergens. In fact, 8 new allergens have been identified and characterized to different degrees. Here, we provide an overview of recent developments concerning the identification and production of recombinant Blomia allergens, as well as their structural and immunological characterization. Although considerable progress has been achieved, detailed molecule-based studies are still needed to better define the clinical relevance of Blomia allergens. Thus, the establishment of a well-standardized and fully characterized panel of allergens remains a challenge for the development of better diagnosis and therapy of allergic diseases induced by B. tropicalis.
Collapse
Affiliation(s)
- Eduardo Santos da Silva
- Laboratório de Alergia e Acarologia, Instituto de Ciências da Saúde, Universidade Federal da Bahia, Salvador, Recife, Brazil
- Programa de Pós-Graduação em Biotecnologia da Rede Nordeste de Biotecnologia (RENORBIO), Recife, Brazil
- Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| | - Claudia Asam
- Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| | - Peter Lackner
- Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| | - Heidi Hofer
- Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| | - Michael Wallner
- Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| | - Carina Silva Pinheiro
- Laboratório de Alergia e Acarologia, Instituto de Ciências da Saúde, Universidade Federal da Bahia, Salvador, Recife, Brazil
| | - Neuza Maria Alcântara-Neves
- Laboratório de Alergia e Acarologia, Instituto de Ciências da Saúde, Universidade Federal da Bahia, Salvador, Recife, Brazil
- Programa de Pós-Graduação em Biotecnologia da Rede Nordeste de Biotecnologia (RENORBIO), Recife, Brazil
| | - Fatima Ferreira
- Department of Molecular Biology, University of Salzburg, Salzburg, Austria
| |
Collapse
|
12
|
Erban T, Harant K, Hubert J. Detailed two-dimensional gel proteomic mapping of the feces of the house dust mite Dermatophagoides pteronyssinus and comparison with D. farinae: Reduced trypsin protease content in D. pteronyssinus and different isoforms. J Proteomics 2017; 162:11-19. [PMID: 28442447 DOI: 10.1016/j.jprot.2017.04.021] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/18/2017] [Accepted: 04/21/2017] [Indexed: 12/25/2022]
Abstract
Major domestic mite allergens are present in feces. We present a detailed 2D-E-MS/MS proteomic analysis of the Dermatophagoides pteronyssinus feces. Precise cultivation yielded a pure fecal extract. We detected differences in fecal allergens/digestive enzymes between D. pteronyssinus and D. farinae using 2D-E fingerprinting, including unique information on species-specific protease isoforms. Proteomic analysis was performed by 2D-E coupled with MALDI-TOF/TOF identification. The species-specific differences in the fecal extracts of the mites were attributed to trypsin-like proteases known as group 3 allergens. In D. farinae, Der f 3 exhibited high abundance with a pI similar (acidic) to that of the cysteine protease Der f 1 and the chymotrypsin protease Der f 6, whereas in D. pteronyssinus, Der p 3 was rarely detected and exhibited low abundance only at basic pI. Moreover, Der p 9 was detected at a pI of ~ 10, in contrast to Der p 1 and Der p 6, suggesting different compartmentalization in the body. Overall, in D. pteronyssinus feces, allergens of groups 1, 2, 6, and 15 were quantitatively similar to those of D. farinae with the exception of the group 3 and 9 allergens. This work provides novel insights into mite-defecated proteins/digestive enzymes, which are important allergens. SIGNIFICANCE Millions of people are affected by allergy and asthma, and their number is growing. In homes, the major triggers of allergy and asthma are the house dust mites Dermatophagoides farinae and D. pteronyssinus, and a clear understanding of the development of diseases caused by these mites is needed. The major sources of mite allergens are their feces, which are deposited in the environment and are easily inhaled as part of aeroplankton. However, descriptions of and comparisons between the major fecal allergens of these two mites are lacking. This study shows that similar group 1 (cysteine protease), 2 (NPC2 family), 6 (chymotrypsin) and 15 (chitinase-like) allergens are present in the feces of these two mite species, as determined by 2D-E mapping, whereas group 3 (trypsin) and 9 (collagenolytic protease) allergens in the feces of the two species are different. The results provide unique MS/MS mapped fingerprints of mite species-specific isoforms in feces. The presence of ubiquitin in mite feces suggests that these proteins participate in the post-translational modification of fecal proteins. The findings are essential for understanding differences between D. farinae and D. pteronyssinus with respect to immunoreactivity, protease activation mechanisms, association with microbes, and food utilization.
Collapse
Affiliation(s)
- Tomas Erban
- Crop Research Institute, Drnovska 507/73, Prague 6-Ruzyne, Czechia.
| | - Karel Harant
- Proteomics Core Facility, Faculty of Science, Charles University, Prague, Czechia
| | - Jan Hubert
- Crop Research Institute, Drnovska 507/73, Prague 6-Ruzyne, Czechia
| |
Collapse
|
13
|
Effects of Glycosylation on the Enzymatic Activity and Mechanisms of Proteases. Int J Mol Sci 2016; 17:ijms17121969. [PMID: 27898009 PMCID: PMC5187769 DOI: 10.3390/ijms17121969] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 11/07/2016] [Accepted: 11/10/2016] [Indexed: 02/06/2023] Open
Abstract
Posttranslational modifications are an important feature of most proteases in higher organisms, such as the conversion of inactive zymogens into active proteases. To date, little information is available on the role of glycosylation and functional implications for secreted proteases. Besides a stabilizing effect and protection against proteolysis, several proteases show a significant influence of glycosylation on the catalytic activity. Glycans can alter the substrate recognition, the specificity and binding affinity, as well as the turnover rates. However, there is currently no known general pattern, since glycosylation can have both stimulating and inhibiting effects on activity. Thus, a comparative analysis of individual cases with sufficient enzyme kinetic and structural data is a first approach to describe mechanistic principles that govern the effects of glycosylation on the function of proteases. The understanding of glycan functions becomes highly significant in proteomic and glycomic studies, which demonstrated that cancer-associated proteases, such as kallikrein-related peptidase 3, exhibit strongly altered glycosylation patterns in pathological cases. Such findings can contribute to a variety of future biomedical applications.
Collapse
|
14
|
Bouaziz A, Walgraffe D, Bouillot C, Herman J, Foguenne J, Gothot A, Louis R, Hentges F, Jacquet A, Mailleux AC, Chevigné A, Galleni M, Adam E, Dumez ME. Development of recombinant stable house dust mite allergen Der p 3 molecules for component-resolved diagnosis and specific immunotherapy. Clin Exp Allergy 2015; 45:823-34. [PMID: 25406386 DOI: 10.1111/cea.12452] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Revised: 07/30/2014] [Accepted: 09/10/2014] [Indexed: 01/22/2023]
Abstract
BACKGROUND The allergen Der p 3 is underrepresented in house dust mite (HDM) extracts probably due to autolysis. Recombinant stable molecule of the allergen is thus needed to improve the diagnosis of allergy and the safety and efficacy of immunotherapy. OBJECTIVE The current study reports the immunological characterization of two recombinant molecules of the HDM allergen Der p 3 as useful tools for diagnosis and immunotherapy. METHODS Recombinant mature (rDer p 3) and immature (proDer p 3) Der p 3 and their corresponding S196A mutants were produced in Pichia pastoris and purified. The stability, IgE-binding capacity and allergenicity of the different proteins were analysed and compared with those of the major mite allergen Der p 1 used as a reference. Additionally, the immunogenicity of the different allergens was evaluated in a murine model of Der p 3 sensitization. RESULTS Compared to the IgE reactivity to recombinant and natural Der p 3 (nDer p 3), the mean IgE binding of patient's sera to rDer p 3-S196A (50%) was higher. The poorly binding to nDer p 3 or rDer p 3 was due to autolysis of the allergen. Contrary to Der p 3, proDer p 3 displayed very weak IgE reactivity, as measured by sandwich ELISA and competitive inhibition, rat basophil leukaemia degranulation and human basophil activation assays. Moreover, proDer p 3 induced a TH 1-biased immune response that prevented allergic response in mice but retained Der p 3-specific T-cell reactivity. CONCLUSION rDer p 3-S196A should be used for the diagnosis of HDM allergy elicited by Der p 3, and proDer p 3 may represent a hypoallergen of Der p 3.
Collapse
Affiliation(s)
- A Bouaziz
- Macromolécules Biologiques, Centre d'ingénierie des Protéines, Université de Liège, Liège, Belgium
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Halim A, Carlsson MC, Madsen CB, Brand S, Møller SR, Olsen CE, Vakhrushev SY, Brimnes J, Wurtzen PA, Ipsen H, Petersen BL, Wandall HH. Glycoproteomic analysis of seven major allergenic proteins reveals novel post-translational modifications. Mol Cell Proteomics 2014; 14:191-204. [PMID: 25389185 DOI: 10.1074/mcp.m114.042614] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Allergenic proteins such as grass pollen and house dust mite (HDM) proteins are known to trigger hypersensitivity reactions of the immune system, leading to what is commonly known as allergy. Key allergenic proteins including sequence variants have been identified but characterization of their post-translational modifications (PTMs) is still limited. Here, we present a detailed PTM(1) characterization of a series of the main and clinically relevant allergens used in allergy tests and vaccines. We employ Orbitrap-based mass spectrometry with complementary fragmentation techniques (HCD/ETD) for site-specific PTM characterization by bottom-up analysis. In addition, top-down mass spectrometry is utilized for targeted analysis of individual proteins, revealing hitherto unknown PTMs of HDM allergens. We demonstrate the presence of lysine-linked polyhexose glycans and asparagine-linked N-acetylhexosamine glycans on HDM allergens. Moreover, we identified more complex glycan structures than previously reported on the major grass pollen group 1 and 5 allergens, implicating important roles for carbohydrates in allergen recognition and response by the immune system. The new findings are important for understanding basic disease-causing mechanisms at the cellular level, which ultimately may pave the way for instigating novel approaches for targeted desensitization strategies and improved allergy vaccines.
Collapse
Affiliation(s)
- Adnan Halim
- From the ‡Copenhagen Center for Glycomics and Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Michael C Carlsson
- From the ‡Copenhagen Center for Glycomics and Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Caroline Benedicte Madsen
- From the ‡Copenhagen Center for Glycomics and Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | | | - Svenning Rune Møller
- From the ‡Copenhagen Center for Glycomics and Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark; ¶Department of Plant and Environmental Biology, Glyco section, Faculty of Science, University of Copenhagen 1871 Frederiksberg C, Denmark
| | - Carl Erik Olsen
- ¶Department of Plant and Environmental Biology, Glyco section, Faculty of Science, University of Copenhagen 1871 Frederiksberg C, Denmark
| | - Sergey Y Vakhrushev
- From the ‡Copenhagen Center for Glycomics and Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | | | | | | | - Bent L Petersen
- From the ‡Copenhagen Center for Glycomics and Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark; ¶Department of Plant and Environmental Biology, Glyco section, Faculty of Science, University of Copenhagen 1871 Frederiksberg C, Denmark
| | - Hans H Wandall
- From the ‡Copenhagen Center for Glycomics and Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, DK-2200 Copenhagen N, Denmark;
| |
Collapse
|
16
|
Dumez ME, Herman J, Campizi V, Galleni M, Jacquet A, Chevigné A. Orchestration of an uncommon maturation cascade of the house dust mite protease allergen quartet. Front Immunol 2014; 5:138. [PMID: 24744761 PMCID: PMC3978338 DOI: 10.3389/fimmu.2014.00138] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 03/18/2014] [Indexed: 11/13/2022] Open
Abstract
In more than 20% of the world population, sensitization to house dust mite allergens triggers typical allergic diseases such as allergic rhinitis and asthma. Amongst the 23 mite allergen groups hitherto identified, group 1 is cysteine proteases belonging to the papain-like family whereas groups 3, 6, and 9 are serine proteases displaying trypsin, chymotrypsin, and collagenolytic activities, respectively. While these proteases are more likely to be involved in the mite digestive system, they also play critical roles in the initiation and in the chronicity of the allergic response notably through the activation of innate immune pathways. All these allergenic proteases are expressed in mite as inactive precursor form. Until recently, the exact mechanisms of their maturation into active proteases remained to be fully elucidated. Recent breakthroughs in the understanding of the activation mechanisms of mite allergenic protease precursors have highlighted an uncommon and unique maturation pathway orchestrated by group 1 proteases that tightly regulates the proteolytic activities of groups 1, 3, 6, and 9 through complex intra- or inter-molecular mechanisms. This review presents and discusses the currently available knowledge of the activation mechanisms of group 1, 3, 6, and 9 allergens of Dermatophagoides pteronyssinus laying special emphasis on their localization, regulation, and interconnection.
Collapse
Affiliation(s)
- Marie-Eve Dumez
- Laboratory of Retrovirology, Department of Infection and Immunity, Centre de Recherche Public Santé , Luxembourg , Luxembourg ; Macromolécules Biologiques, Department of Life Sciences, Centre for Protein Engineering, University of Liège , Liège , Belgium
| | - Julie Herman
- Macromolécules Biologiques, Department of Life Sciences, Centre for Protein Engineering, University of Liège , Liège , Belgium
| | - Vincenzo Campizi
- Laboratory of Retrovirology, Department of Infection and Immunity, Centre de Recherche Public Santé , Luxembourg , Luxembourg ; Macromolécules Biologiques, Department of Life Sciences, Centre for Protein Engineering, University of Liège , Liège , Belgium
| | - Moreno Galleni
- Macromolécules Biologiques, Department of Life Sciences, Centre for Protein Engineering, University of Liège , Liège , Belgium
| | - Alain Jacquet
- Faculty of Medicine, Department of Medicine, Division of Allergy and Clinical Immunology, Chulalongkorn University , Bangkok , Thailand
| | - Andy Chevigné
- Laboratory of Retrovirology, Department of Infection and Immunity, Centre de Recherche Public Santé , Luxembourg , Luxembourg
| |
Collapse
|
17
|
Herman J, Thelen N, Smargiasso N, Mailleux AC, Luxen A, Cloes M, De Pauw E, Chevigné A, Galleni M, Dumez ME. Der p 1 is the primary activator of Der p 3, Der p 6 and Der p 9 the proteolytic allergens produced by the house dust mite Dermatophagoides pteronyssinus. Biochim Biophys Acta Gen Subj 2013; 1840:1117-24. [PMID: 24291687 DOI: 10.1016/j.bbagen.2013.11.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 10/30/2013] [Accepted: 11/18/2013] [Indexed: 11/16/2022]
Abstract
BACKGROUND The enzymatic activity of the four proteases found in the house dust mite Dermatophagoides pteronyssinus is involved in the pathogenesis of allergy. Our aim was to elucidate the activation cascade of their corresponding precursor forms and particularly to highlight the interconnection between proteases during this cascade. METHODS The cleavage of the four peptides corresponding to the mite zymogen activation sites was studied on the basis of the Förster Resonance Energy Transfer method. The proDer p 6 zymogen was then produced in Pichia pastoris to elucidate its activation mechanism by mite proteases, especially Der p 1. The role of the propeptide in the inhibition of the enzymatic activity of Der p 6 was also examined. Finally, the Der p 1 and Der p 6 proteases were localised via immunolocalisation in D. pteronyssinus. RESULTS All peptides were specifically cleaved by Der p 1, such as proDer p 6. The propeptide of proDer p 6 inhibited the proteolytic activity of Der p 6, but once cleaved, it was degraded by the protease. The Der p 1 and Der p 6 proteases were both localised to the midgut of the mite. CONCLUSIONS Der p 1 in either its recombinant form or in the natural context of house dust mite extracts specifically cleaves all zymogens, thus establishing its role as a major activator of both mite cysteine and serine proteases. GENERAL SIGNIFICANCE This finding suggests that Der p 1 may be valuable target against mites.
Collapse
Affiliation(s)
- Julie Herman
- Macromolécules Biologiques, Centre for Protein Engineering, University of Liège, 4000 Liège, Belgium
| | - Nicolas Thelen
- Unit of Cell and Tissue Biology, GIGA-Neurosciences, University of Liège, 4000 Liège, Belgium
| | - Nicolas Smargiasso
- Mass Spectrometry Laboratory, GIGA-R, Department of Chemistry, University of Liège, 4000 Liège, Belgium
| | | | - André Luxen
- Centre de Recherche du Cyclotron, University of Liège, 4000 Liège, Belgium
| | - Marie Cloes
- Unit of Cell and Tissue Biology, GIGA-Neurosciences, University of Liège, 4000 Liège, Belgium
| | - Edwin De Pauw
- Mass Spectrometry Laboratory, GIGA-R, Department of Chemistry, University of Liège, 4000 Liège, Belgium
| | - Andy Chevigné
- Laboratory of Retrovirology, CRP-Santé, 1526 Luxembourg, Luxembourg
| | - Moreno Galleni
- Macromolécules Biologiques, Centre for Protein Engineering, University of Liège, 4000 Liège, Belgium.
| | - Marie-Eve Dumez
- Macromolécules Biologiques, Centre for Protein Engineering, University of Liège, 4000 Liège, Belgium; Laboratory of Retrovirology, CRP-Santé, 1526 Luxembourg, Luxembourg
| |
Collapse
|
18
|
Dumez ME, Herman J, Campisi V, Bouaziz A, Rosu F, Luxen A, Vandenberghe I, de Pauw E, Frère JM, Matagne A, Chevigné A, Galleni M. The proline-rich motif of the proDer p 3 allergen propeptide is crucial for protease-protease interaction. PLoS One 2013; 8:e68014. [PMID: 24073192 PMCID: PMC3779199 DOI: 10.1371/journal.pone.0068014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 05/24/2013] [Indexed: 11/19/2022] Open
Abstract
The majority of proteases are synthesized in an inactive form, termed zymogen, which consists of a propeptide and a protease domain. The propeptide is commonly involved in the correct folding and specific inhibition of the enzyme. The propeptide of the house dust mite allergen Der p 3, NPILPASPNAT, contains a proline-rich motif (PRM), which is unusual for a trypsin-like protease. By truncating the propeptide or replacing one or all of the prolines in the non-glycosylated zymogen with alanine(s), we demonstrated that the full-length propeptide is not required for correct folding and thermal stability and that the PRM is important for the resistance of proDer p 3 to undesired proteolysis when the protein is expressed in Pichia pastoris. Additionally, we followed the maturation time course of proDer p 3 by coupling a quenched-flow assay to mass spectrometry analysis. This approach allowed to monitor the evolution of the different species and to determine the steady-state kinetic parameters for activation of the zymogen by the major allergen Der p 1. This experiment demonstrated that prolines 5 and 8 are crucial for proDer p 3-Der p 1 interaction and for activation of the zymogen.
Collapse
Affiliation(s)
- Marie-Eve Dumez
- Macromolécules Biologiques, Centre for Protein Engineering, Université de Liège, Liège, Belgium
| | - Julie Herman
- Macromolécules Biologiques, Centre for Protein Engineering, Université de Liège, Liège, Belgium
| | - Vincenzo Campisi
- Macromolécules Biologiques, Centre for Protein Engineering, Université de Liège, Liège, Belgium
- Laboratoire de Rétrovirologie, Centre de Recherche Public de la Santé, Luxembourg, Luxembourg
| | - Ahlem Bouaziz
- Macromolécules Biologiques, Centre for Protein Engineering, Université de Liège, Liège, Belgium
| | - Frédéric Rosu
- Laboratoire de spectrométrie de masse (L.S.M.), GIGA-R, Université de Liège, Liège, Belgium
| | - André Luxen
- Centre de Recherches du cyclotron, Université de Liège, Liège, Belgium
| | - Isabel Vandenberghe
- Laboratory for Protein Biochemistry and Protein Engineering, K.L. Ledeganckstraat 35B, Gent, Belgium
| | - Edwin de Pauw
- Laboratoire de spectrométrie de masse (L.S.M.), GIGA-R, Université de Liège, Liège, Belgium
| | - Jean-Marie Frère
- Macromolécules Biologiques, Centre for Protein Engineering, Université de Liège, Liège, Belgium
- Laboratoire d'enzymologie et repliement des protéines, Centre for Protein Engineering, Université de Liège, Liège, Belgium
| | - André Matagne
- Laboratoire d'enzymologie et repliement des protéines, Centre for Protein Engineering, Université de Liège, Liège, Belgium
| | - Andy Chevigné
- Macromolécules Biologiques, Centre for Protein Engineering, Université de Liège, Liège, Belgium
- Laboratoire de Rétrovirologie, Centre de Recherche Public de la Santé, Luxembourg, Luxembourg
| | - Moreno Galleni
- Macromolécules Biologiques, Centre for Protein Engineering, Université de Liège, Liège, Belgium
- * E-mail:
| |
Collapse
|
19
|
Baldo A, Chevigné A, Dumez ME, Mathy A, Power P, Tabart J, Cambier L, Galleni M, Mignon B. Inhibition of the keratinolytic subtilisin protease Sub3 from Microsporum canis by its propeptide (proSub3) and evaluation of the capacity of proSub3 to inhibit fungal adherence to feline epidermis. Vet Microbiol 2012; 159:479-84. [DOI: 10.1016/j.vetmic.2012.04.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2012] [Revised: 04/29/2012] [Accepted: 04/30/2012] [Indexed: 10/28/2022]
|
20
|
Chevigné A, Dumez ME, Dumoulin M, Matagne A, Jacquet A, Galleni M. Comparative study of mature and zymogen mite cysteine protease stability and pH unfolding. Biochim Biophys Acta Gen Subj 2010; 1800:937-45. [PMID: 20682463 DOI: 10.1016/j.bbagen.2010.05.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 05/14/2010] [Accepted: 05/24/2010] [Indexed: 11/26/2022]
Abstract
BACKGROUND Papain-like proteases (CA1) are synthesized as inactive precursors carrying an N-terminal propeptide, which is further removed under acidic conditions to generate active enzymes. METHODS To have a better insight into the mechanism of activation of this protease family, we compared the pH unfolding of the zymogen and the mature form of the mite cysteine protease Der p 1. RESULTS We showed that the presence of the propeptide does not significantly influence the pH-induced unfolding of the catalytic domain but does affect its fluorescence properties by modifying the exposure of the tryptophan 192 to the solvent. In addition, we demonstrated that the propeptide displays weaker pH stability than the protease domain confirming that the unfolding of the propeptide is the key event in the activation process of the zymogen. GENERAL SIGNIFICANCE Finally, we show, using thermal denaturation and enzymatic activity measurements, that whatever the pH value, the propeptide does not stabilize the structure of the catalytic domain but very interestingly, prevents its autolysis.
Collapse
Affiliation(s)
- Andy Chevigné
- Macromolécules Biologiques, Centre d'Ingénierie des Protéines, Université de Liège, Institut de Chimie B6, Sart Tilman Liège B-4000, Belgique
| | | | | | | | | | | |
Collapse
|
21
|
Dvorák J, Mashiyama ST, Sajid M, Braschi S, Delcroix M, Schneider EL, McKerrow WH, Bahgat M, Hansell E, Babbitt PC, Craik CS, McKerrow JH, Caffrey CR. SmCL3, a gastrodermal cysteine protease of the human blood fluke Schistosoma mansoni. PLoS Negl Trop Dis 2009; 3:e449. [PMID: 19488406 PMCID: PMC2685030 DOI: 10.1371/journal.pntd.0000449] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Accepted: 05/01/2009] [Indexed: 12/23/2022] Open
Abstract
Background Blood flukes of the genus Schistosoma are platyhelminth parasites that infect 200 million people worldwide. Digestion of nutrients from the host bloodstream is essential for parasite development and reproduction. A network of proteolytic enzymes (proteases) facilitates hydrolysis of host hemoglobin and serum proteins. Methodology/Principal Findings We identified a new cathepsin L termed SmCL3 using PCR strategies based on S. mansoni EST sequence data. An ortholog is present in Schistosoma japonicum. SmCL3 was heterologously expressed as an active enzyme in the yeast, Pichia pastoris. Recombinant SmCL3 has a broad pH activity range against peptidyl substrates and is inhibited by Clan CA protease inhibitors. Consistent with a function in degrading host proteins, SmCL3 hydrolyzes serum albumin and hemoglobin, is localized to the adult gastrodermis, and is expressed mainly in those life stages infecting the mammalian host. The predominant form of SmCL3 in the parasite exists as a zymogen, which is unusual for proteases. This zymogen includes an unusually long prodomain with alpha helical secondary structure motifs. The striking specificity of SmCL3 for amino acids with large aromatic side chains (Trp and Tyr) at the P2 substrate position, as determined with positional scanning-synthetic combinatorial library, is consistent with a molecular model that shows a large and deep S2 pocket. A sequence similarity network (SSN) view clusters SmCL3 and other cathepsins L in accordance with previous large-scale phylogenetic analyses that identify six super kingdoms. Conclusions/Significance SmCL3 is a gut-associated cathepsin L that may contribute to the network of proteases involved in degrading host blood proteins as nutrients. Furthermore, this enzyme exhibits some unusual sequence and biophysical features that may result in additional functions. The visualization of network inter-relationships among cathepsins L suggests that these enzymes are suitable ‘marker sequences’ for inclusion in future phylogenetic analyses. Parasitic infection caused by blood flukes of the genus Schistosoma is a major global health problem. More than 200 million people are infected. Identifying and characterizing the constituent enzymes of the parasite's biochemical pathways should reveal opportunities for developing new therapies (i.e., vaccines, drugs). Schistosomes feed on host blood, and a number of proteolytic enzymes (proteases) contribute to this process. We have identified and characterized a new protease, SmCL3 (for Schistosoma mansoni cathepsin L3), that is found within the gut tissue of the parasite. We have employed various biochemical and molecular biological methods and sequence similarity analyses to characterize SmCL3 and obtain insights into its possible functions in the parasite, as well as its evolutionary position among cathepsin L proteases in general. SmCL3 hydrolyzes major host blood proteins (serum albumin and hemoglobin) and is expressed in parasite life stages infecting the mammalian host. Enzyme substrate specificity detected by positional scanning-synthetic combinatorial library was confirmed by molecular modeling. A sequence analysis placed SmCL3 to the cluster of other cathepsins L in accordance with previous phylogenetic analyses.
Collapse
Affiliation(s)
- Jan Dvorák
- Sandler Center for Basic Research in Parasitic Diseases, California Institute for Quantitative Biosciences, University of California San Francisco, San Francisco, California, United States of America.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|