1
|
Wang CR, McFarlane LO, Pukala TL. Exploring snake venoms beyond the primary sequence: From proteoforms to protein-protein interactions. Toxicon 2024; 247:107841. [PMID: 38950738 DOI: 10.1016/j.toxicon.2024.107841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 06/26/2024] [Accepted: 06/28/2024] [Indexed: 07/03/2024]
Abstract
Snakebite envenomation has been a long-standing global issue that is difficult to treat, largely owing to the flawed nature of current immunoglobulin-based antivenom therapy and the complexity of snake venoms as sophisticated mixtures of bioactive proteins and peptides. Comprehensive characterisation of venom compositions is essential to better understanding snake venom toxicity and inform effective and rationally designed antivenoms. Additionally, a greater understanding of snake venom composition will likely unearth novel biologically active proteins and peptides that have promising therapeutic or biotechnological applications. While a bottom-up proteomic workflow has been the main approach for cataloguing snake venom compositions at the toxin family level, it is unable to capture snake venom heterogeneity in the form of protein isoforms and higher-order protein interactions that are important in driving venom toxicity but remain underexplored. This review aims to highlight the importance of understanding snake venom heterogeneity beyond the primary sequence, in the form of post-translational modifications that give rise to different proteoforms and the myriad of higher-order protein complexes in snake venoms. We focus on current top-down proteomic workflows to identify snake venom proteoforms and further discuss alternative or novel separation, instrumentation, and data processing strategies that may improve proteoform identification. The current higher-order structural characterisation techniques implemented for snake venom proteins are also discussed; we emphasise the need for complementary and higher resolution structural bioanalytical techniques such as mass spectrometry-based approaches, X-ray crystallography and cryogenic electron microscopy, to elucidate poorly characterised tertiary and quaternary protein structures. We envisage that the expansion of the snake venom characterisation "toolbox" with top-down proteomics and high-resolution protein structure determination techniques will be pivotal in advancing structural understanding of snake venoms towards the development of improved therapeutic and biotechnology applications.
Collapse
Affiliation(s)
- C Ruth Wang
- Discipline of Chemistry, School of Physics, Chemistry and Earth Sciences, The University of Adelaide, Adelaide, 5005, Australia
| | - Lewis O McFarlane
- Discipline of Chemistry, School of Physics, Chemistry and Earth Sciences, The University of Adelaide, Adelaide, 5005, Australia
| | - Tara L Pukala
- Discipline of Chemistry, School of Physics, Chemistry and Earth Sciences, The University of Adelaide, Adelaide, 5005, Australia.
| |
Collapse
|
2
|
Tan CH, Tan KY, Ng TS, Tan NH, Chong HP. De Novo Venom Gland Transcriptome Assembly and Characterization for Calloselasma rhodostoma (Kuhl, 1824), the Malayan Pit Viper from Malaysia: Unravelling Toxin Gene Diversity in a Medically Important Basal Crotaline. Toxins (Basel) 2023; 15:toxins15050315. [PMID: 37235350 DOI: 10.3390/toxins15050315] [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: 03/31/2023] [Revised: 04/24/2023] [Accepted: 04/26/2023] [Indexed: 05/28/2023] Open
Abstract
In Southeast Asia, the Malayan Pit Viper (Calloselasma rhodostoma) is a venomous snake species of medical importance and bioprospecting potential. To unveil the diversity of its toxin genes, this study de novo assembled and analyzed the venom gland transcriptome of C. rhodostoma from Malaysia. The expression of toxin genes dominates the gland transcriptome by 53.78% of total transcript abundance (based on overall FPKM, Fragments Per Kilobase Million), in which 92 non-redundant transcripts belonging to 16 toxin families were identified. Snake venom metalloproteinase (SVMP, PI > PII > PIII) is the most dominant family (37.84% of all toxin FPKM), followed by phospholipase A2 (29.02%), bradykinin/angiotensin-converting enzyme inhibitor-C-type natriuretic peptide (16.30%), C-type lectin (CTL, 10.01%), snake venom serine protease (SVSP, 2.81%), L-amino acid oxidase (2.25%), and others (1.78%). The expressions of SVMP, CTL, and SVSP correlate with hemorrhagic, anti-platelet, and coagulopathic effects in envenoming. The SVMP metalloproteinase domains encode hemorrhagins (kistomin and rhodostoxin), while disintegrin (rhodostomin from P-II) acts by inhibiting platelet aggregation. CTL gene homologues uncovered include rhodocytin (platelet aggregators) and rhodocetin (platelet inhibitors), which contribute to thrombocytopenia and platelet dysfunction. The major SVSP is a thrombin-like enzyme (an ancrod homolog) responsible for defibrination in consumptive coagulopathy. The findings provide insight into the venom complexity of C. rhodostoma and the pathophysiology of envenoming.
Collapse
Affiliation(s)
- Choo Hock Tan
- Department of Pharmacology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Kae Yi Tan
- Department of Molecular Medicine, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Tzu Shan Ng
- Department of Molecular Medicine, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Nget Hong Tan
- Department of Molecular Medicine, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| | - Ho Phin Chong
- Department of Pharmacology, Faculty of Medicine, Universiti Malaya, Kuala Lumpur 50603, Malaysia
| |
Collapse
|
3
|
Dohnálek J, Skálová T. C-type lectin-(like) fold - Protein-protein interaction patterns and utilization. Biotechnol Adv 2022; 58:107944. [PMID: 35301089 DOI: 10.1016/j.biotechadv.2022.107944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 03/04/2022] [Accepted: 03/07/2022] [Indexed: 11/02/2022]
Abstract
The C-type lectin-like fold (CTL fold) is a building block of many proteins, including saccharide-binding lectins, natural killer cell receptors, macrophage mannose receptor, selectins, collectins, snake venoms and others. Some are important players in innate immunity and are involved in the first-line response to virally infected cells or cancer cells, some play a role in antimicrobial defense, and some are potential targets for fight against problems connected with allergies, obesity, and autoimmunity. The structure of a CTL domain typically contains two α-helices, two small β-sheets and a long surface loop, with two or three disulfide bridges stabilizing the structure. This small domain is often involved in interactions with a target molecule, however, utilizing varied parts of the domain surface, with or without structural modifications. More than 500 three-dimensional structures of CTL fold-containing proteins are available in the Protein Data Bank, including a significant number of complexes with their key interacting partners (protein:protein complexes). The amount of available structural data enables a detailed analysis of the rules of interaction patterns utilized in activation, inhibition, attachment and other pathways or functionalities. Interpretation of known CTL receptor structures and all other CTL-containing proteins and complexes with described three-dimensional structures, complemented with sequence/structure/interaction correlation analysis offers a comprehensive view of the rules of interaction patterns of the CTL fold. The results are of value for prediction of interaction behavior of so far not understood CTL-containing proteins and development of new protein binders based on this fold, with applications in biomedicine or biotechnologies. It follows from the available structural data that almost the whole surface of the CTL fold is utilized in protein:protein interactions, with the heaviest frequency of utilization in the canonical interaction region. The individual categories of interactions differ in the interface buildup strategy. The strongest CTL binders rely on interfaces with large interaction area, presence of hydrophobic core, or high surface complementarity. The typical interaction surfaces of the fold are not conserved in amino acid sequence and can be utilized in design of new binders for biotechnological applications.
Collapse
Affiliation(s)
- Jan Dohnálek
- Institute of Biotechnology of the Czech Academy of Sciences, Biocev, Průmyslová 595, 25250 Vestec, Czech Republic.
| | - Tereza Skálová
- Institute of Biotechnology of the Czech Academy of Sciences, Biocev, Průmyslová 595, 25250 Vestec, Czech Republic
| |
Collapse
|
4
|
Eble JA. Structurally Robust and Functionally Highly Versatile-C-Type Lectin (-Related) Proteins in Snake Venoms. Toxins (Basel) 2019; 11:toxins11030136. [PMID: 30823637 PMCID: PMC6468738 DOI: 10.3390/toxins11030136] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 02/19/2019] [Accepted: 02/20/2019] [Indexed: 12/31/2022] Open
Abstract
Snake venoms contain an astounding variety of different proteins. Among them are numerous C-type lectin family members, which are grouped into classical Ca2+- and sugar-binding lectins and the non-sugar-binding snake venom C-type lectin-related proteins (SV-CLRPs), also called snaclecs. Both groups share the robust C-type lectin domain (CTLD) fold but differ in a long loop, which either contributes to a sugar-binding site or is expanded into a loop-swapping heterodimerization domain between two CLRP subunits. Most C-type lectin (-related) proteins assemble in ordered supramolecular complexes with a high versatility of subunit numbers and geometric arrays. Similarly versatile is their ability to inhibit or block their target molecules as well as to agonistically stimulate or antagonistically blunt a cellular reaction triggered by their target receptor. By utilizing distinct interaction sites differentially, SV-CLRPs target a plethora of molecules, such as distinct coagulation factors and receptors of platelets and endothelial cells that are involved in hemostasis, thrombus formation, inflammation and hematogenous metastasis. Because of their robust structure and their high affinity towards their clinically relevant targets, SV-CLRPs are and will potentially be valuable prototypes to develop new diagnostic and therapeutic tools in medicine, provided that the molecular mechanisms underlying their versatility are disclosed.
Collapse
Affiliation(s)
- Johannes A Eble
- Institute of Physiological Chemistry and Pathobiochemistry, University of Münster, Waldeyerstr. 15, 48149 Münster, Germany.
| |
Collapse
|
5
|
Estevão-Costa MI, Sanz-Soler R, Johanningmeier B, Eble JA. Snake venom components in medicine: From the symbolic rod of Asclepius to tangible medical research and application. Int J Biochem Cell Biol 2018; 104:94-113. [PMID: 30261311 DOI: 10.1016/j.biocel.2018.09.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 09/03/2018] [Accepted: 09/19/2018] [Indexed: 12/21/2022]
Abstract
Both mythologically and logically, snakes have always fascinated man. Snakes have attracted both awe and fear not only because of the elegant movement of their limbless bodies, but also because of the potency of their deadly venoms. Practically, in 2017, the world health organization (WHO) listed snake envenomation as a high priority neglected disease, as snakes inflict up to 2.7 million poisonous bites, around 100.000 casualties, and about three times as many invalidities on man. The venoms of poisonous snakes are a cocktail of potent compounds which specifically and avidly target numerous essential molecules with high efficacy. The individual effects of all venom toxins integrate into lethal dysfunctions of almost any organ system. It is this efficacy and specificity of each venom component, which after analysis of its structure and activity may serve as a potential lead structure for chemical imitation. Such toxin mimetics may help in influencing a specific body function pharmaceutically for the sake of man's health. In this review article, we will give some examples of snake venom components which have spurred the development of novel pharmaceutical compounds. Moreover, we will provide examples where such snake toxin-derived mimetics are in clinical use, trials, or consideration for further pharmaceutical exploitation, especially in the fields of hemostasis, thrombosis, coagulation, and metastasis. Thus, it becomes clear why a snake captured its symbolic place at the Asclepius rod with good reason still nowadays.
Collapse
Affiliation(s)
- Maria-Inacia Estevão-Costa
- Institute of Physiological Chemistry and Pathobiochemistry, University of Münster, Waldeyerstr. 15, 48149, Münster, Germany
| | - Raquel Sanz-Soler
- Institute of Physiological Chemistry and Pathobiochemistry, University of Münster, Waldeyerstr. 15, 48149, Münster, Germany
| | - Benjamin Johanningmeier
- Institute of Physiological Chemistry and Pathobiochemistry, University of Münster, Waldeyerstr. 15, 48149, Münster, Germany
| | - Johannes A Eble
- Institute of Physiological Chemistry and Pathobiochemistry, University of Münster, Waldeyerstr. 15, 48149, Münster, Germany.
| |
Collapse
|
6
|
Purification and Characterization of a Novel Antiplatelet Peptide from Deinagkistrodon acutus Venom. Toxins (Basel) 2018; 10:toxins10080332. [PMID: 30115892 PMCID: PMC6115707 DOI: 10.3390/toxins10080332] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 08/13/2018] [Accepted: 08/14/2018] [Indexed: 01/06/2023] Open
Abstract
Animal venoms are considered as one of the most important sources for drug development. Deinagkistrodon acutus is famous for its toxicity to the human hematological system and envenomed patients develop a coagulation disorder with the symptoms of hemorrhage and microthrombi formation. The purpose of this study was to separate antiplatelet peptides from D. acutus venom using a combination of an ultrafiltration technique and reversed-phase high performance liquid chromatography (HPLC), which was guided by monitoring antiplatelet aggregation bioactivity. A novel octa-peptide named DAA-8 was found. This peptide inhibited protease-activated receptor1 (PAR-1) agonist (SFLLRN-NH2) induced platelet aggregation and it also inhibited platelet aggregation induced by thrombin, ADP, and collagen. Furthermore, DAA-8 showed significant antithrombotic activity and resulted in a slightly increased bleeding risk in vivo. This is the first report of a peptide derived from snake venom, which inhibited PAR-1 agonist-induced platelet aggregation. This peptide may provide a template to design a new PAR-1 inhibitor.
Collapse
|
7
|
Rhodocetin-αβ selectively breaks the endothelial barrier of the tumor vasculature in HT1080 fibrosarcoma and A431 epidermoid carcinoma tumor models. Oncotarget 2018; 9:22406-22422. [PMID: 29854288 PMCID: PMC5976474 DOI: 10.18632/oncotarget.25032] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 03/19/2018] [Indexed: 11/29/2022] Open
Abstract
The tumor vasculature differs from normal blood vessels in morphology, composition and stability. Here, we describe a novel tumor vessel-disrupting mechanism. In an HT1080/mouse xenograft tumor model rhodocetin-αβ was highly effective in disrupting the tumor endothelial barrier. Mechanistically, rhodocetin-αβ triggered MET signaling via neuropilin-1. As both neuropilin-1 and MET were only lumen-exposed in a subset of abnormal tumor vessels, but not in normal vessels, the prime target of rhodocetin-αβ were these abnormal tumor vessels. Consequently, cells lining such tumor vessels became increasingly motile which compromised the vessel wall tightness. After this initial leakage, rhodocetin-αβ could leave the bloodstream and reach the as yet inaccessible neuropilin-1 on the basolateral side of endothelial cells and thus disrupt nearby vessels. Due to the specific neuropilin-1/MET co-distribution on cells lining such abnormal tumor vessels in contrast to normal endothelial cells, rhodocetin-αβ formed the necessary trimeric signaling complex of rhodocetin-αβ-MET-neuropilin-1 only in these abnormal tumor vessels. This selective attack of tumor vessels, sparing endothelial cell-lined vessels of normal tissues, suggests that the neuropilin-1-MET signaling axis may be a promising drugable target for anti-tumor therapy, and that rhodocetin-αβ may serve as a lead structure to develop novel anti-tumor drugs that target such vessels.
Collapse
|
8
|
Eble JA. Titration ELISA as a Method to Determine the Dissociation Constant of Receptor Ligand Interaction. J Vis Exp 2018. [PMID: 29553569 DOI: 10.3791/57334] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The dissociation constant describes the interaction between two partners in the binding equilibrium and is a measure of their affinity. It is a crucial parameter to compare different ligands, e.g., competitive inhibitors, protein isoforms and mutants, for their binding strength to a binding partner. Dissociation constants are determined by plotting concentrations of bound versus free ligand as binding curves. In contrast, titration curves, in which a signal that is proportional to the concentration of bound ligand is plotted against the total concentration of added ligand, are much easier to record. The signal can be detected spectroscopically and by enzyme-linked immunosorbent assay (ELISA). This is exemplified in a protocol for a titration ELISA that measures the binding of the snake venom-derived rhodocetin to its immobilized target domain of α2β1 integrin. Titration ELISAs are versatile and widely used. Any pair of interacting proteins can be used as immobilized receptor and soluble ligand, provided that both proteins are pure, and their concentrations are known. The difficulty so far has been to determine the dissociation constant from a titration curve. In this study, a mathematical function underlying titration curves is introduced. Without any error-prone graphical estimation of a saturation yield, this algorithm allows processing of the raw data (signal intensities at different concentrations of added ligand) directly by mathematical evaluation via non-linear regression. Thus, several titration curves can be recorded simultaneously and transformed into a set of characteristic parameters, among them the dissociation constant and the concentration of binding-active receptor, and they can be evaluated statistically. When combined with this algorithm, titration ELISAs gain the advantage of directly presenting the dissociation constant. Therefore, they may be used more efficiently in the future.
Collapse
Affiliation(s)
- Johannes A Eble
- Institute of Physiological Chemistry and Pathobiochemistry, University of Münster;
| |
Collapse
|
9
|
Dramatic and concerted conformational changes enable rhodocetin to block α2β1 integrin selectively. PLoS Biol 2017; 15:e2001492. [PMID: 28704364 PMCID: PMC5509089 DOI: 10.1371/journal.pbio.2001492] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 06/15/2017] [Indexed: 01/08/2023] Open
Abstract
The collagen binding integrin α2β1 plays a crucial role in hemostasis, fibrosis, and cancer progression amongst others. It is specifically inhibited by rhodocetin (RC), a C-type lectin-related protein (CLRP) found in Malayan pit viper (Calloselasma rhodostoma) venom. The structure of RC alone reveals a heterotetramer arranged as an αβ and γδ subunit in a cruciform shape. RC specifically binds to the collagen binding A-domain of the integrin α2 subunit, thereby blocking collagen-induced platelet aggregation. However, until now, the molecular basis for this interaction has remained unclear. Here, we present the molecular structure of the RCγδ-α2A complex solved to 3.0 Å resolution. Our findings show that RC undergoes a dramatic structural reorganization upon binding to α2β1 integrin. Besides the release of the nonbinding RCαβ tandem, the RCγ subunit interacts with loop 2 of the α2A domain as result of a dramatic conformational change. The RCδ subunit contacts the integrin α2A domain in the “closed” conformation through its helix C. Combined with epitope-mapped antibodies, conformationally locked α2A domain mutants, point mutations within the α2A loop 2, and chemical modifications of the purified toxin protein, this molecular structure of RCγδ-α2A complex explains the inhibitory mechanism and specificity of RC for α2β1 integrin. In animals, collagen-mediated platelet aggregation is an essential component of the blood’s clotting response following vascular injury. A small group of snake venom toxins belonging to the C-type lectin protein family exert their harmful effects by directly targeting this pathway. Rhodocetin (RC) is a heterotetrameric protein found in the venom of the Malayan pit viper (C. rhodostoma). RC specifically binds α2β1 integrin, the key protein required for collagen-mediated platelet aggregation. In this study, we describe the interaction between RC and α2β1 integrin at atomic resolution. This study reveals that RC undergoes a massive structural reorganization upon α2β1 integrin binding, such that RC’s αβ subunit is released from its γδ subunit and a γδ-α2β1 integrin complex is formed. The inhibitory nature of this complex can be readily explained as RC binding along the top surface of the α2β1 integrin and directly above the collagen binding site. As a result, access of collagen to its binding site is blocked, thereby preventing collagen-mediated platelet aggregation.
Collapse
|
10
|
Tang ELH, Tan CH, Fung SY, Tan NH. Venomics of Calloselasma rhodostoma, the Malayan pit viper: A complex toxin arsenal unraveled. J Proteomics 2016; 148:44-56. [PMID: 27418434 DOI: 10.1016/j.jprot.2016.07.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 06/26/2016] [Accepted: 07/07/2016] [Indexed: 12/22/2022]
Abstract
UNLABELLED The venom of Malayan pit viper (Calloselasma rhodostoma) is highly toxic but also valuable in drug discovery. However, a comprehensive proteome of the venom that details its toxin composition and abundance is lacking. This study aimed to unravel the venom complexity through a multi-step venomic approach. At least 96 distinct proteins (29 basic, 67 acidic) in 11 families were identified from the venom. The venom consists of mainly snake venom metalloproteinases (SVMP, 41.17% of total venom proteins), within which the P-I (kistomin, 20.4%) and P-II (rhodostoxin, 19.8%) classes predominate. This is followed by C-type lectins (snaclec, 26.3%), snake venom serine protease (SVSP, 14.9%), L-amino acid oxidase (7.0%), phospholipase A2 (4.4%), cysteine-rich secretory protein (2.5%), and five minor toxins (nerve growth factor, neurotrophin, phospholipase B, 5' nucleotidase and phosphodiesterase, totaling 2.6%) not reported in the proteome hitherto. Importantly, all principal hemotoxins unveiled correlate with the syndrome: SVSP ancrod causes venom-induced consumptive coagulopathy, aggravated by thrombocytopenia caused by snaclec rhodocytin, a platelet aggregation inducer, while P-II rhodostoxin mediates hemorrhage, exacerbated by P-I kistomin and snaclec rhodocetin that inhibit platelet plug formation. These toxins exist in multiple isoforms and/or complex subunits, deserving further characterization for the development of an effective, polyspecific regional antivenom. BIOLOGICAL SIGNIFICANCE Advents in proteomics and bioinformatics have vigorously propelled the scientific discoveries of toxins from various lineages of venomous snakes. The Malayan pit viper, Calloselasma rhodostoma, is a medically important species in Southeast Asia as its bite can cause envenomation, while the venom is also a source of bioactive compounds for drug discovery. Detailed profiling of the venom, however, is inadequate possibly due to the complex nature of the venom and technical limitation in separating the constituents into details. Integrating a multi-step fractionation method, this study successfully revealed a comprehensive and quantitative profile of the composition of the venom of this medically important venomous snake. The relative abundance of the various venom proteins is determined in a global profile, providing useful information for understanding the pathogenic roles of the different toxins in C. rhodostoma envenomation. Notably, the principal hemotoxins were identified in great details, including the variety of toxin subunits and isoforms. The findings indicate that these toxins are the principal targets for effective antivenom neutralization, and should be addressed in the production of a pan-regional polyspecific antivenom. In addition, minor toxin components not reported previously in the venom were also detected in this study, enriching the current toxin database for the venomous snakes.
Collapse
Affiliation(s)
- Esther Lai Har Tang
- Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Choo Hock Tan
- Department of Pharmacology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
| | - Shin Yee Fung
- Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Nget Hong Tan
- Department of Molecular Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
| |
Collapse
|
11
|
Jebali J, Fakhfekh E, Morgen M, Srairi-Abid N, Majdoub H, Gargouri A, El Ayeb M, Luis J, Marrakchi N, Sarray S. Lebecin, a new C-type lectin like protein from Macrovipera lebetina venom with anti-tumor activity against the breast cancer cell line MDA-MB231. Toxicon 2014; 86:16-27. [PMID: 24814013 DOI: 10.1016/j.toxicon.2014.04.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 04/15/2014] [Accepted: 04/29/2014] [Indexed: 01/20/2023]
Abstract
C-type lectins like proteins display various biological activities and are known to affect especially platelet aggregation. Few of them have been reported to have anti-tumor effects. In this study, we have identified and characterized a new C-type lectin like protein, named lebecin. Lebecin is a heterodimeric protein of 30 kDa. The N-terminal amino acid sequences of both subunits were determined by Edman degradation and the entire amino acid sequences were deduced from cDNAs. The precursors of both lebecin subunits contain a 23-amino acid residue signal peptide and the mature α and β subunits are composed of 129 and 131 amino acids, respectively. Lebecin is shown to be a potent inhibitor of MDA-MB231 human breast cancer cells proliferation. Furthermore, lebecin dose-dependently inhibited the integrin-mediated attachment of these cells to different adhesion substrata. This novel C-type lectin also completely blocked MDA-MB231 cells migration towards fibronectin and fibrinogen in haptotaxis assays.
Collapse
Affiliation(s)
- Jed Jebali
- Laboratoire des venins et biomolécules thérapeutiques, Institut Pasteur de Tunis, B.P. 74, 1002 Tunis Belvédère, Tunisia.
| | - Emna Fakhfekh
- Laboratoire des venins et biomolécules thérapeutiques, Institut Pasteur de Tunis, B.P. 74, 1002 Tunis Belvédère, Tunisia
| | - Maram Morgen
- Laboratoire des venins et biomolécules thérapeutiques, Institut Pasteur de Tunis, B.P. 74, 1002 Tunis Belvédère, Tunisia
| | - Najet Srairi-Abid
- Laboratoire des venins et biomolécules thérapeutiques, Institut Pasteur de Tunis, B.P. 74, 1002 Tunis Belvédère, Tunisia
| | - Hafedh Majdoub
- USCR séquenceur de protéines, Faculté des sciences de Sfax, Route de Soukra, km 3.5, BP 1171, 3000 Sfax, Tunisia
| | - Ali Gargouri
- Laboratoire de Valorisation de la Biomasse et Production de Protéines chez les Eucaryotes, Centre de la Biotechnologie de Sfax (CBS), Tunisia
| | - Mohamed El Ayeb
- Laboratoire des venins et biomolécules thérapeutiques, Institut Pasteur de Tunis, B.P. 74, 1002 Tunis Belvédère, Tunisia
| | - José Luis
- Aix Marseille Université, Institut National de la Santé et de la Recherche Médicale, UMR_S 911, Marseille, France
| | - Naziha Marrakchi
- Laboratoire des venins et biomolécules thérapeutiques, Institut Pasteur de Tunis, B.P. 74, 1002 Tunis Belvédère, Tunisia
| | - Sameh Sarray
- Laboratoire des venins et biomolécules thérapeutiques, Institut Pasteur de Tunis, B.P. 74, 1002 Tunis Belvédère, Tunisia; Faculté des Sciences de Tunis, Université de Tunis El Manar, 2092, Tunisia
| |
Collapse
|
12
|
Bolás G, de Rezende FF, Lorente C, Sanz L, Eble JA, Calvete JJ. Inhibitory effects of recombinant RTS-jerdostatin on integrin α1β1 function during adhesion, migration and proliferation of rat aortic smooth muscle cells and angiogenesis. Toxicon 2014; 79:45-54. [PMID: 24418176 DOI: 10.1016/j.toxicon.2013.12.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 11/22/2013] [Accepted: 12/18/2013] [Indexed: 10/25/2022]
Abstract
Jerdostatin, a short RTS-disintegrin cloned from venom gland mRNA of Protobothrops jerdonii, selectively blocks the adhesion of α1β1 integrin to collagen IV. Integrin α1β1 is highly expressed in smooth muscle cells (SMC) surrounding small blood vessels and vascular endothelial cells. Vascular SMC adhesion, migration and proliferation are important processes during normal vascular development. Using recombinant jerdostatin we have investigated the role of the α1β1 integrin on the adhesion of vascular SMC to collagen IV, and the potential relevance of blocking this crucial component of focal adhesions as an anti-angiogenic strategy. Our results show that jerdostatin does not interact with canonical collagen-binding site on the isolated A-domain of the α1 integrin subunit. r-Jerdostatin inhibited the adhesion of RASMCs to immobilized CB3 fragment in a dose-dependent manner, triggering to round-up, retraction, and finally detachment of the cells. r-Jerdostatin did not affect the adhesion of human SMCs to CB3, presumably because the high expression of α2β1 integrin compensated for α1β1 integrin blockage by jerdostatin. r-Jerdostatin dose-dependently inhibited α1β1 integrin-dependent HUVEC tube formation. However, VEGF-driven tube formation in the matrigel assay was only completely abolished when binding of integrin α2β1 to collagen was also inhibited by the C-type lectin-like rhodocetin. As a whole, our work emphasizes the relevance of using specific inhibitors for dissecting the role of α1β1 integrin in physiological and pathological conditions.
Collapse
Affiliation(s)
- Gema Bolás
- Instituto de Biomedicina de Valencia, CSIC, Valencia, Spain
| | - Flávia Figueiredo de Rezende
- Institute for Physiological Chemistry and Pathobiochemistry, University of Muenster, Waldeyerstr. 15, 48149 Muenster, Germany
| | | | - Libia Sanz
- Instituto de Biomedicina de Valencia, CSIC, Valencia, Spain
| | - Johannes A Eble
- Institute for Physiological Chemistry and Pathobiochemistry, University of Muenster, Waldeyerstr. 15, 48149 Muenster, Germany
| | - Juan J Calvete
- Instituto de Biomedicina de Valencia, CSIC, Valencia, Spain.
| |
Collapse
|
13
|
Brennan M, Cox D. The therapeutic potential of I-domain integrins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 819:157-78. [PMID: 25023174 DOI: 10.1007/978-94-017-9153-3_11] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Due to their role in processes central to cancer and autoimmune disease I-domain integrins are an attractive drug target. Both antibodies and small molecule antagonists have been discovered and tested in the clinic. Much of the effort has focused on αLβ2 antagonists. Maybe the most successful was the monoclonal antibody efalizumab, which was approved for the treatment of psoriasis but subsequently withdrawn from the market due to the occurrence of a serious adverse effect (progressive multifocal leukoencephalopathy). Other monoclonal antibodies were tested for the treatment of reperfusion injury, post-myocardial infarction, but failed to progress due to lack of efficacy. New potent small molecule inhibitors of αv integrins are promising reagents for treating fibrotic disease. Small molecule inhibitors targeting collagen-binding integrins have been discovered and future work will focus on identifying molecules selectively targeting each of the collagen receptors and identifying appropriate target diseases for future clinical studies.
Collapse
Affiliation(s)
- Marian Brennan
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, 123 St. Stephen's Green, Dublin 2, Ireland
| | | |
Collapse
|
14
|
Applications of snake venom components to modulate integrin activities in cell-matrix interactions. Int J Biochem Cell Biol 2013; 45:1974-86. [PMID: 23811033 DOI: 10.1016/j.biocel.2013.06.009] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 05/29/2013] [Accepted: 06/12/2013] [Indexed: 01/23/2023]
Abstract
Snake venom proteins are broadly investigated in the different areas of life science. Direct interaction of these compounds with cells may involve a variety of mechanisms that result in diverse cellular responses leading to the activation or blocking of physiological functions of the cell. In this review, the snake venom components interacting with integrins will be characterized in context of their effect on cellular response. Currently, two major families of snake venom proteins are considered as integrin-binding molecules. The most attention has been devoted to the disintegrin family, which binds certain types of integrins through specific motifs recognized as a tri-peptide structurally localized on an integrin-binding loop. Other snake venom integrin-binding proteins belong to the C-type lectin family. Snake venom molecules bind to the cellular integrins resulting in a modulation of cell signaling and in consequence, the regulation of cell proliferation, migration and apoptosis. Therefore, snake venom research on the integrin-binding molecules may have significance in biomedicine and basic cell biology.
Collapse
|
15
|
Jakubowski P, Calvete JJ, Eble JA, Lazarovici P, Marcinkiewicz C. Identification of inhibitors of α2β1 integrin, members of C-lectin type proteins, in Echis sochureki venom. Toxicol Appl Pharmacol 2013; 269:34-42. [PMID: 23499869 DOI: 10.1016/j.taap.2013.03.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 02/26/2013] [Accepted: 03/01/2013] [Indexed: 10/27/2022]
Abstract
Snake venom antagonists of α2β1 integrin have been identified as members of a C-lectin type family of proteins (CLP). In the present study, we characterized three new CLPs isolated from Echis sochureki venom, which interact with this integrin. These proteins were purified using a combination of gel filtration, ion exchange chromatography and reverse phase HPLC. Sochicetin-A and sochicetin-B potently inhibited adhesion of cells expressing α2β1 integrin and binding of isolated α2β1 ectodomain to collagen I, as well as bound to recombinant GST-α2A domain in ELISA, whereas activity of sochicetin-C in these assays was approximately two orders of magnitude lower. Structurally, sochicetin-B and sochicetin-C are typical heterodimeric αβ CLPs, whereas sochicetin-A exhibits a trimer of its subunits (αβ)₃ in the quaternary structure. Immobilized sochicetins supported adhesion of glioma cell lines, LN18 and LBC3, whereas in a soluble form they partially inhibited adhesion of these cells to collagen I. Glioma cells spread very poorly on sochicetin-A, showing no cytoskeleton rearrangement typical for adhesion to collagen I or fibronectin. Adhesion on CLP does not involve focal adhesion elements, such as vinculin. Sochicetin-A also inhibited collagen-induced platelet aggregation, similar to other CLPs' action on the blood coagulation system.
Collapse
Affiliation(s)
- Piotr Jakubowski
- Department of Biology, Temple University, Philadelphia, PA 19122, USA
| | | | | | | | | |
Collapse
|
16
|
Identification of α2β1 integrin inhibitor VP-i with anti-platelet properties in the venom of Vipera palaestinae. Toxicon 2013; 64:96-105. [PMID: 23319078 DOI: 10.1016/j.toxicon.2013.01.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 12/14/2012] [Accepted: 01/04/2013] [Indexed: 01/12/2023]
Abstract
Integrins are receptors of the extracellular matrix (ECM), playing a vital role in pathophysiological processes. They bind to ECM ligands like collagens and can mediate wound healing as well as tumor metastasis and thrombosis, thus being a part of cell adhesion and migration as well as platelet aggregation. For this reason, identifying α2β1 integrin-specific antagonists can assist in the development of drugs to treat tumor progression, angiogenesis, and cardiovascular diseases. Snake venoms have been shown to contain antagonists which target collagen-binding integrins. EMS16, rhodocetin, and VP12 are three toxins belonging to the C-type lectin-related protein family and have been proven to inhibit the α2β1 integrin, specifically the α2 integrin A domain. To specifically isolate antagonists targeting the α2β1 integrin A domain, we developed a protocol based on affinity chromatography. Using this novel approach, the toxin VP-i was isolated from Vipera palaestinae venom. We show that VP-i binds to the α2 integrin A domain and that it successfully inhibits adhesion of various cells to type I collagen as well as cell migration. Moreover, our results indicate that VP-i differs structurally from the previously purified VP12, although not functionally, and therefore is a further venom compound which can be utilized for drug development.
Collapse
|
17
|
Niland S, Ditkowski B, Parrandier D, Roth L, Augustin H, Eble JA. Rhodocetin-αβ-induced neuropilin-1-cMet association triggers restructuring of matrix contacts in endothelial cells. Arterioscler Thromb Vasc Biol 2013; 33:544-54. [PMID: 23288161 DOI: 10.1161/atvbaha.112.00006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
OBJECTIVE The snake venom component rhodocetin-αβ (RCαβ) stimulates endothelial cell motility in an α2β1 integrin-independent manner. We aimed to elucidate its cellular and molecular mechanisms. METHODS AND RESULTS We identified neuropilin-1 (Nrp1) as a novel target of RCαβ by protein-chemical methods. RCαβ and vascular endothelial growth factor (VEGF)-A avidly bind to Nrp1. Instead of acting as VEGF receptor 2 coreceptor, Nrp1 associates upon RCαβ treatment with cMet. Furthermore, cell-based ELISAs and kinase inhibitor studies showed that RCαβ induces phosphorylation of tyrosines 1234/1235 [corrected] and thus activation of cMet. Consequently, paxillin is phosphorylated at Y31, which is redistributed from streak-like focal adhesions to spot-like focal contacts at the cell perimeter, along with α2β1 integrin, thereby regulating cell-matrix interactions. Cortactin is abundant in the cell perimeter, where it is involved in the branching of the cortical actin network of lamellipodia, whereas tensile force-bearing actin stress fibers radiating from focal adhesions disappear together with zyxin, a focal adhesion marker, on RCαβ treatment. CONCLUSIONS Our data demonstrate that (1) Nrp1 is a novel target for venom components, such as RCαβ; (2) Nrp1 coupled to cMet regulates the type of cell-matrix interactions in a manner involving paxillin phosphorylation; and (3) altered cell-matrix interactions determine endothelial cell migration and cellular force management.
Collapse
Affiliation(s)
- Stephan Niland
- Center for Molecular Medicine, Vascular Matrix Biology, Excellence Cluster Cardio-Pulmonary System, Frankfurt University Hospital, Frankfurt, Germany
| | | | | | | | | | | |
Collapse
|
18
|
Arlinghaus FT, Eble JA. The collagen-binding integrin α2β1 is a novel interaction partner of the Trimeresurus flavoviridis venom protein flavocetin-A. J Biol Chem 2012. [PMID: 23204528 DOI: 10.1074/jbc.m112.399618] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Many snake venoms are known for their antithrombotic activity. They contain components that specifically target different platelet-activating receptors such as the collagen-binding integrin α2β1 and the von Willebrand factor receptor GPIb. In a search for an α2β1 integrin-blocking component from the venom of the habu snake (Trimeresurus flavoviridis), we employed two independent purification protocols. First, we used the integrin α2A domain, a major collagen-binding domain, as bait for affinity purification of an α2β1 integrin-binding toxin from the crude venom. Second, in parallel, we used classical protein separation protocols and tested for α2β1 integrin-inhibiting capabilities by ELISA. Using both approaches, we identified flavocetin-A as an inhibitor of α2β1 integrin. Hitherto, flavocetin-A has been reported as a GPIb inhibitor. However, flavocetin-A inhibited collagen-induced platelet aggregation even after GPIb was blocked with other inhibitors. Moreover, flavocetin-A antagonized α2β1 integrin-mediated adhesion and migration of HT1080 human fibrosarcoma cells, which lack any GPIb, on collagen. Protein chemical analyses proved that flavocetin-A binds to α2β1 integrin and its α2A domain with high affinity and in a cooperative manner, which most likely is due to its quaternary structure. Kinetic measurements confirmed the formation of a strong complex between integrin and flavocetin-A, which dissociates very slowly. This study proves that flavocetin-A, which has long been known as a GPIb inhibitor, efficiently targets α2β1 integrin and thus blocks collagen-induced platelet activation. Moreover, our findings suggest that the separation of GPIb- and α2β1 integrin-blocking members within the C-type lectin-related protein family is less strict than previously assumed.
Collapse
Affiliation(s)
- Franziska T Arlinghaus
- Center for Molecular Medicine, Department of Vascular Matrix Biology, Excellence Cluster Cardio-Pulmonary System, Frankfurt University Hospital, 60590 Frankfurt, Germany
| | | |
Collapse
|
19
|
C-type lectin-like proteins from snake venoms. Toxicon 2012; 60:512-9. [DOI: 10.1016/j.toxicon.2012.03.001] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 02/28/2012] [Accepted: 03/01/2012] [Indexed: 11/21/2022]
|
20
|
Vaiyapuri S, Hutchinson EG, Ali MS, Dannoura A, Stanley RG, Harrison RA, Bicknell AB, Gibbins JM. Rhinocetin, a venom-derived integrin-specific antagonist inhibits collagen-induced platelet and endothelial cell functions. J Biol Chem 2012; 287:26235-44. [PMID: 22689571 PMCID: PMC3406708 DOI: 10.1074/jbc.m112.381483] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Snaclecs are small non-enzymatic proteins present in viper venoms reported to modulate hemostasis of victims through effects on platelets, vascular endothelial, and smooth muscle cells. In this study, we have isolated and functionally characterized a snaclec that we named "rhinocetin" from the venom of West African gaboon viper, Bitis gabonica rhinoceros. Rhinocetin was shown to comprise α and β chains with the molecular masses of 13.5 and 13 kDa, respectively. Sequence and immunoblot analysis of rhinocetin confirmed this to be a novel snaclec. Rhinocetin inhibited collagen-stimulated activation of human platelets in a dose-dependent manner but displayed no inhibitory effects on glycoprotein VI (collagen receptor) selective agonist, CRP-XL-, ADP-, or thrombin-induced platelet activation. Rhinocetin antagonized the binding of monoclonal antibodies against the α2 subunit of integrin α2β1 to platelets and coimmunoprecipitation analysis confirmed integrin α2β1 as a target for this venom protein. Rhinocetin inhibited a range of collagen-induced platelet functions such as fibrinogen binding, calcium mobilization, granule secretion, aggregation, and thrombus formation. It also inhibited integrin α2β1-dependent functions of human endothelial cells. Together, our data suggest rhinocetin to be a modulator of integrin α2β1 function and thus may provide valuable insights into the role of this integrin in physiological and pathophysiological scenarios, including hemostasis, thrombosis, and envenomation.
Collapse
Affiliation(s)
- Sakthivel Vaiyapuri
- Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, Reading RG6 6UB, United Kingdom
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Momic T, Arlinghaus FT, Arien-Zakay H, Katzhendler J, Eble JA, Marcinkiewicz C, Lazarovici P. Pharmacological aspects of Vipera xantina palestinae venom. Toxins (Basel) 2011; 3:1420-32. [PMID: 22174978 PMCID: PMC3237004 DOI: 10.3390/toxins3111420] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Revised: 10/03/2011] [Accepted: 11/01/2011] [Indexed: 01/03/2023] Open
Abstract
In Israel, Vipera xantina palestinae (V.x.p.) is the most common venomous snake, accounting for several hundred cases of envenomation in humans and domestic animals every year, with a mortality rate of 0.5 to 2%. In this review we will briefly address the research developments relevant to our present understanding of the structure and function of V.x.p. venom with emphasis on venom disintegrins. Venom proteomics indicated the presence of four families of pharmacologically active compounds: (i) neurotoxins; (ii) hemorrhagins; (iii) angioneurin growth factors; and (iv) different types of integrin inhibitors. Viperistatin, a α1β1selective KTS disintegrin and VP12, a α2β1 selective C-type lectin were discovered. These snake venom proteins represent promising tools for research and development of novel collagen receptor selective drugs. These discoveries are also relevant for future improvement of antivenom therapy towards V.x.p. envenomation.
Collapse
Affiliation(s)
- Tatjana Momic
- School of Pharmacy Institute for Drug Research, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel; (T.M.); (H.A.-Z.); (J.K.)
| | - Franziska T. Arlinghaus
- Center for Molecular Medicine, Department of Vascular Matrix Biology, Frankfurt University Hospital, Excellence Cluster Cardio-Pulmonary System, 60590 Frankfurt, Germany; (F.T.A); (J.A.E.)
| | - Hadar Arien-Zakay
- School of Pharmacy Institute for Drug Research, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel; (T.M.); (H.A.-Z.); (J.K.)
| | - Jeoshua Katzhendler
- School of Pharmacy Institute for Drug Research, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel; (T.M.); (H.A.-Z.); (J.K.)
| | - Johannes A. Eble
- Center for Molecular Medicine, Department of Vascular Matrix Biology, Frankfurt University Hospital, Excellence Cluster Cardio-Pulmonary System, 60590 Frankfurt, Germany; (F.T.A); (J.A.E.)
| | - Cezary Marcinkiewicz
- Department of Biology, Temple University College of Science and Technology, Philadelphia, PA 19122, USA;
| | - Philip Lazarovici
- School of Pharmacy Institute for Drug Research, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel; (T.M.); (H.A.-Z.); (J.K.)
| |
Collapse
|
22
|
Monoclonal antibodies reveal the alteration of the rhodocetin structure upon α2β1 integrin binding. Biochem J 2011; 440:1-11. [DOI: 10.1042/bj20110584] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The α2β1 antagonist rhodocetin from Calloselasma rhodostoma is a heterotetrameric CLRP (C-type lectin-related protein) consisting of four distinct chains, α, β, γ and δ. Via their characteristic domain-swapping loops, the individual chains form two subunits, αβ and γδ. To distinguish the four chains which share similar molecular masses and high sequence homologies, we generated 11 mAbs (monoclonal antibodies) with different epitope specificities. Four groups of distinct mAbs were generated: the first targeted the rhodocetin β chain, the second group bound to the αβ subunit mostly in a conformation-dependent manner, the third group recognized the γδ subunit only when separated from the αβ subunit, whereas a fourth group interacted with the γδ subunit both in the heterotetrameric molecule and complexed with the integrin α2 A-domain. Using the specific mAbs, we have shown that the rhodocetin heterotetramer dissociates into the αβ and γδ subunit upon binding to the integrin α2 A-domain at both the molecular and cellular levels. After dissociation, the γδ subunit firmly interacts with the α2β1 integrin, thereby blocking it, whereas the rhodocetin αβ subunit is released from the complex. The small molecular interface between the αβ and γδ subunits within rhodocetin is mostly mediated by charged residues, which causes the two dissociated subunits to have hydrophilic surfaces.
Collapse
|
23
|
Naumann GB, Silva LF, Silva L, Faria G, Richardson M, Evangelista K, Kohlhoff M, Gontijo CM, Navdaev A, de Rezende FF, Eble JA, Sanchez EF. Cytotoxicity and inhibition of platelet aggregation caused by an l-amino acid oxidase from Bothrops leucurus venom. Biochim Biophys Acta Gen Subj 2011; 1810:683-94. [DOI: 10.1016/j.bbagen.2011.04.003] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 03/20/2011] [Accepted: 04/14/2011] [Indexed: 12/09/2022]
|
24
|
Navdaev A, Lochnit G, Eble JA. The rhodocetin αβ subunit targets GPIb and inhibits von Willebrand factor induced platelet activation. Toxicon 2011; 57:1041-8. [PMID: 21524659 DOI: 10.1016/j.toxicon.2011.04.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Revised: 04/04/2011] [Accepted: 04/06/2011] [Indexed: 11/29/2022]
Abstract
Rhodocetin, a heterotetrameric snake C-type lectin from Calloselasma rhodostoma is a specific antagonist of α2β1 integrin. Its γδ subunit is responsible for binding to α2β1 integrin. In this study we show that the rhodocetin αβ subunit can bind to platelet glycoprotein GPIb. Binding of the rhodocetin αβ subunit does not depend on divalent cations. When added to washed human platelets the rhodocetin αβ subunit effectively inhibits platelet aggregation induced by von Willebrand factor plus ristocetin. In contrast, it does not affect collagen-induced platelet activation. By itself the rhodocetin αβ subunit does not induce any changes when added to washed platelets or platelet-rich plasma. However, rhodocetin αβ, after biotinylation and cross-linkage with avidin induces small platelet agglutination but not aggregation. These agglutinated platelets change their pattern of protein tyrosine phosphorylation slightly as kinase p72SYK but not p125FAK is phosphorylated.
Collapse
Affiliation(s)
- Alexey Navdaev
- Excellence Cluster Cardio-Pulmonary System, Center for Molecular Medicine, Dept. Vascular Matrix Biology, Frankfurt University Hospital, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
| | | | | |
Collapse
|
25
|
Clemetson KJ. Snaclecs (snake C-type lectins) that inhibit or activate platelets by binding to receptors. Toxicon 2010; 56:1236-46. [DOI: 10.1016/j.toxicon.2010.03.011] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2010] [Accepted: 03/15/2010] [Indexed: 11/25/2022]
|
26
|
Eble JA. Matrix biology meets toxinology. Matrix Biol 2010; 29:239-47. [PMID: 20079834 DOI: 10.1016/j.matbio.2010.01.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Revised: 01/07/2010] [Accepted: 01/11/2010] [Indexed: 02/05/2023]
Abstract
Venoms are cocktails containing pharmacologically active compounds, which drastically affect essential functions of the neuromuscular and cardiovascular system, as well as of blood, kidney and other organs. As the extracellular matrix and its contacts with cells are responsible for maintaining the integrity and functionality of these organs and tissues, it is not surprising that several venom components target matrix molecules and their respective cellular receptors. Many venom components, such as matrix-degrading enzymes, disintegrins, and C-type lectin-like proteins, have been identified and have laid the foundation for the frontier research field of matrix toxinology. Interestingly, many toxins consist of domains which are structurally homologous to modules and domains of matrix proteins, their proteinases and cellular receptors. In addition to finding new agents and tools, which specifically interact with matrix molecules and their receptors, the characterization of known matrix-targeting toxins will provide insights into their molecular modes of action and thus may lead to potential new therapeutic strategies for treating matrix-related diseases, such as blood clotting and thrombocyte-mediated disorders, but also tumor malignancies.
Collapse
Affiliation(s)
- Johannes A Eble
- Excellence Cluster Cardio-Pulmonary System, Center for Molecular Medicine, Dept. Vascular Matrix Biology, Frankfurt University Hospital, Bldg 9, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
| |
Collapse
|