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Coimbra FCP, Sanchez EE, Lomonte B, Gutiérrez JM, Calvete JJ, Fry BG. Blood Lines: Intraspecific and Interspecific Variations in Anticoagulant Actions of Agkistrodon Viperid Venoms. Toxins (Basel) 2024; 16:291. [PMID: 39057931 PMCID: PMC11281148 DOI: 10.3390/toxins16070291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2024] [Revised: 06/23/2024] [Accepted: 06/25/2024] [Indexed: 07/28/2024] Open
Abstract
This study investigated the intraspecific and interspecific variability in the venom effects of Agkistrodon viperid snake species and subspecies (eleven venoms total) on plasma clotting times, fibrinogen levels, and fibrin clot strength. Significant delays in plasma clotting time were observed for A. conanti, A. contortrix mokasen, A. contortrix phaeogaster, A. howardgloydi, A. piscivorus leucostoma, and A. piscivorus piscivorus. Notably, the phylogenetically disjunct lineages A. conanti, A. contortrix mokasen, and A. howardgloydi exhibited the most potent anticoagulant effects, indicating the independent amplification of a basal trait. Inhibition assays with the activated clotting enzymes Factors XIa, IXa, Xa, and IIa (thrombin) revealed that FXa inhibition is another basal trait amplified independently on multiple occasions within the genus, but with A. howardgloydi, notably more potent than all others. Phospholipid degradation and zymogen destruction were identified as mechanisms underlying the variability in venom effects observed experimentally and in previous clinical reports. Thromboelastography demonstrated that the venoms did not clot fibrinogen directly but affected fibrin clot strength by damaging fibrinogen and that thrombin was subsequently only able to cleave into weak, unstable clots. The ability to activate Protein C, an endogenous anticoagulant enzyme, varied across species, with some venoms exceeding that of A. contortrix contortrix, which previously yielded the protein diagnostic agent Protac®. Phylogenetic analysis suggested that both fibrinogen degradation and Protein C activation were each amplified multiple times within the genus, albeit with negative correlation between these two modes of action. This study highlights the evolutionary, clinical, and biodiscovery implications of venom variability in the Agkistrodon species, underscoring their dynamic evolution, emphasising the need for tailored clinical approaches, and highlighting the potential for novel diagnostic and therapeutic developments inspired by the unique properties of snake venoms.
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Affiliation(s)
- Francisco C. P. Coimbra
- Adaptive Biotoxicology Lab, School of the Environment, University of Queensland, St Lucia, QLD 4072, Australia;
| | - Elda E. Sanchez
- National Natural Toxins Research Center, Department of Chemistry, Texas A&M University-Kingsville, MSC 224, 975 West Avenue B, Kingsville, TX 78363, USA;
| | - Bruno Lomonte
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José 11501, Costa Rica; (B.L.); (J.M.G.)
| | - José María Gutiérrez
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, San José 11501, Costa Rica; (B.L.); (J.M.G.)
| | - Juan J. Calvete
- Laboratorio de Venómica Evolutiva y Traslacional, Instituto de Biomedicina de Valencia, CSIC, 46010 Valencia, Spain;
| | - Bryan G. Fry
- Adaptive Biotoxicology Lab, School of the Environment, University of Queensland, St Lucia, QLD 4072, Australia;
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Dobson J, Chowdhury A, Tai-A-Pin J, van der Ploeg H, Gillett A, Fry BG. The Clot Thickens: Differential Coagulotoxic and Cardiotoxic Activities of Anguimorpha Lizard Venoms. Toxins (Basel) 2024; 16:283. [PMID: 38922177 PMCID: PMC11209219 DOI: 10.3390/toxins16060283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Revised: 06/11/2024] [Accepted: 06/17/2024] [Indexed: 06/27/2024] Open
Abstract
Despite their evolutionary novelty, lizard venoms are much less studied in comparison to the intense research on snake venoms. While the venoms of helodermatid lizards have long been assumed to be for defensive purposes, there is increasing evidence of toxic activities more useful for predation than defence (such as paralytic neurotoxicity). This study aimed to ascertain the effects of Heloderma, Lanthanotus, and Varanus lizard venoms on the coagulation and cardiovascular systems. Anticoagulant toxicity was demonstrated for the Varanus species studied, with the venoms prolonging clotting times in human and bird plasma due to the destructive cleavage of fibrinogen. In contrast, thromboelastographic analyses on human and bird plasmas in this study demonstrated a procoagulant bioactivity for Heloderma venoms. A previous study on Heloderma venom using factor-depleted plasmas as a proxy model suggested a procoagulant factor was present that activated either Factor XI or Factor XII, but could not ascertain the precise target. Our activation studies using purified zymogens confirmed FXII activation. Comparisons of neonate and adult H. exasperatum, revealed the neonates to be more potent in the ability to activate FXII, being more similar to the venom of the smaller species H. suspectum than the adult H. exasperatum. This suggests potent FXII activation a basal trait in the genus, present in the small bodied last common ancestor. This also indicates an ontogenetic difference in prey preferences in the larger Heloderma species paralleing the change in venom biochemistry. In addition, as birds lack Factor XII, the ability to clot avian plasma suggested an additional procoagulant site of action, which was revealed to be the activation of Factor VII, with H. horridum being the most potent. This study also examined the effects upon the cardiovascular system, including the liberation of kinins from kininogen, which contributes to hypotension induction. This form of toxicity was previously described for Heloderma venoms, and was revealed in this study was to also be a pathophysiological effect of Lanthanotus and Varanus venoms. This suggests that this toxic activity was present in the venom of the last common ancestor of the anguimorph lizards, which is consistent with kallikrein enzymes being a shared toxin trait. This study therefore uncovered novel actions of anguimorph lizard venoms, not only contributing to the evolutionary biology body of knowledge but also revealing novel activities to mine for drug design lead compounds.
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Affiliation(s)
- James Dobson
- Adaptive Biotoxicology Lab, School of the Environment, University of Queensland, St Lucia, QLD 4072, Australia; (J.D.); (A.C.)
| | - Abhinandan Chowdhury
- Adaptive Biotoxicology Lab, School of the Environment, University of Queensland, St Lucia, QLD 4072, Australia; (J.D.); (A.C.)
| | | | - Harold van der Ploeg
- Working Group Adder Research Netherlands, RAVON, 6525 ED Nijmegen, The Netherlands;
| | - Amber Gillett
- FaunaVet Wildlife Consultancy, Glass House Mountains, QLD 4518, Australia;
| | - Bryan G. Fry
- Adaptive Biotoxicology Lab, School of the Environment, University of Queensland, St Lucia, QLD 4072, Australia; (J.D.); (A.C.)
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Jmel MA, Aounallah H, Bensaoud C, Mekki I, Chmelař J, Faria F, M’ghirbi Y, Kotsyfakis M. Insights into the Role of Tick Salivary Protease Inhibitors during Ectoparasite-Host Crosstalk. Int J Mol Sci 2021; 22:E892. [PMID: 33477394 PMCID: PMC7831016 DOI: 10.3390/ijms22020892] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 01/12/2021] [Accepted: 01/13/2021] [Indexed: 02/07/2023] Open
Abstract
Protease inhibitors (PIs) are ubiquitous regulatory proteins present in all kingdoms. They play crucial tasks in controlling biological processes directed by proteases which, if not tightly regulated, can damage the host organism. PIs can be classified according to their targeted proteases or their mechanism of action. The functions of many PIs have now been characterized and are showing clinical relevance for the treatment of human diseases such as arthritis, hepatitis, cancer, AIDS, and cardiovascular diseases, amongst others. Other PIs have potential use in agriculture as insecticides, anti-fungal, and antibacterial agents. PIs from tick salivary glands are special due to their pharmacological properties and their high specificity, selectivity, and affinity to their target proteases at the tick-host interface. In this review, we discuss the structure and function of PIs in general and those PI superfamilies abundant in tick salivary glands to illustrate their possible practical applications. In doing so, we describe tick salivary PIs that are showing promise as drug candidates, highlighting the most promising ones tested in vivo and which are now progressing to preclinical and clinical trials.
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Affiliation(s)
- Mohamed Amine Jmel
- Laboratory of Genomics and Proteomics of Disease Vectors, Biology Centre CAS, Institute of Parasitology, Branišovská 1160/31, 37005 České Budějovice, Czech Republic; (M.A.J.); (C.B.); (I.M.)
| | - Hajer Aounallah
- Institut Pasteur de Tunis, Université de Tunis El Manar, LR19IPTX, Service d’Entomologie Médicale, Tunis 1002, Tunisia; (H.A.); (Y.M.)
- Innovation and Development Laboratory, Innovation and Development Center, Instituto Butantan, São Paulo 05503-900, Brazil;
| | - Chaima Bensaoud
- Laboratory of Genomics and Proteomics of Disease Vectors, Biology Centre CAS, Institute of Parasitology, Branišovská 1160/31, 37005 České Budějovice, Czech Republic; (M.A.J.); (C.B.); (I.M.)
| | - Imen Mekki
- Laboratory of Genomics and Proteomics of Disease Vectors, Biology Centre CAS, Institute of Parasitology, Branišovská 1160/31, 37005 České Budějovice, Czech Republic; (M.A.J.); (C.B.); (I.M.)
- Faculty of Science, University of South Bohemia in České Budějovice, 37005 České Budějovice, Czech Republic;
| | - Jindřich Chmelař
- Faculty of Science, University of South Bohemia in České Budějovice, 37005 České Budějovice, Czech Republic;
| | - Fernanda Faria
- Innovation and Development Laboratory, Innovation and Development Center, Instituto Butantan, São Paulo 05503-900, Brazil;
| | - Youmna M’ghirbi
- Institut Pasteur de Tunis, Université de Tunis El Manar, LR19IPTX, Service d’Entomologie Médicale, Tunis 1002, Tunisia; (H.A.); (Y.M.)
| | - Michalis Kotsyfakis
- Laboratory of Genomics and Proteomics of Disease Vectors, Biology Centre CAS, Institute of Parasitology, Branišovská 1160/31, 37005 České Budějovice, Czech Republic; (M.A.J.); (C.B.); (I.M.)
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Blisnick AA, Foulon T, Bonnet SI. Serine Protease Inhibitors in Ticks: An Overview of Their Role in Tick Biology and Tick-Borne Pathogen Transmission. Front Cell Infect Microbiol 2017; 7:199. [PMID: 28589099 PMCID: PMC5438962 DOI: 10.3389/fcimb.2017.00199] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 05/04/2017] [Indexed: 01/01/2023] Open
Abstract
New tick and tick-borne pathogen control approaches that are both environmentally sustainable and which provide broad protection are urgently needed. Their development, however, will rely on a greater understanding of tick biology, tick-pathogen, and tick-host interactions. The recent advances in new generation technologies to study genomes, transcriptomes, and proteomes has resulted in a plethora of tick biomacromolecular studies. Among these, many enzyme inhibitors have been described, notably serine protease inhibitors (SPIs), whose importance in various tick biological processes is only just beginning to be fully appreciated. Among the multiple active substances secreted during tick feeding, SPIs have been shown to be directly involved in regulation of inflammation, blood clotting, wound healing, vasoconstriction and the modulation of host defense mechanisms. In light of these activities, several SPIs were examined and were experimentally confirmed to facilitate tick pathogen transmission. In addition, to prevent coagulation of the ingested blood meal within the tick alimentary canal, SPIs are also involved in blood digestion and nutrient extraction from the meal. The presence of SPIs in tick hemocytes and their involvement in tick innate immune defenses have also been demonstrated, as well as their implication in hemolymph coagulation and egg development. Considering the involvement of SPIs in multiple crucial aspects of tick-host-pathogen interactions, as well as in various aspects of the tick parasitic lifestyle, these molecules represent highly suitable and attractive targets for the development of effective tick control strategies. Here we review the current knowledge regarding this class of inhibitors in tick biology and tick-borne pathogen transmission, and their potential as targets for future tick control trials.
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Affiliation(s)
| | - Thierry Foulon
- Centre National de la Recherche Scientifique, Institut de Biologie Paris-Seine, Biogenèse des Signaux Peptidiques, Sorbonne Universités, UPMC Univ. Paris 06Paris, France
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Afosah DK, Al-Horani RA, Sankaranarayanan NV, Desai UR. Potent, Selective, Allosteric Inhibition of Human Plasmin by Sulfated Non-Saccharide Glycosaminoglycan Mimetics. J Med Chem 2017; 60:641-657. [DOI: 10.1021/acs.jmedchem.6b01474] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Daniel K. Afosah
- Department of Medicinal Chemistry,
and Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, Virginia 23219, United States
| | - Rami A. Al-Horani
- Department of Medicinal Chemistry,
and Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, Virginia 23219, United States
| | - Nehru Viji Sankaranarayanan
- Department of Medicinal Chemistry,
and Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, Virginia 23219, United States
| | - Umesh R. Desai
- Department of Medicinal Chemistry,
and Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, Virginia 23219, United States
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Soares TS, Oliveira F, Torquato RJ, Sasaki SD, Araujo MS, Paschoalin T, Tanaka AS. BmTI-A, a Kunitz type inhibitor from Rhipicephalus microplus able to interfere in vessel formation. Vet Parasitol 2016; 219:44-52. [DOI: 10.1016/j.vetpar.2016.01.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Revised: 12/23/2015] [Accepted: 01/27/2016] [Indexed: 11/30/2022]
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Vijay S, Rawal R, Kadian K, Raghavendra K, Sharma A. Annotated differentially expressed salivary proteins of susceptible and insecticide-resistant mosquitoes of Anopheles stephensi. PLoS One 2015; 10:e0119666. [PMID: 25742511 PMCID: PMC4351086 DOI: 10.1371/journal.pone.0119666] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 01/15/2015] [Indexed: 01/17/2023] Open
Abstract
Vector control is one of the major global strategies for control of malaria. However, the major obstacle for vector control is the development of multiple resistances to organochlorine, organophosphorus insecticides and pyrethroids that are currently being used in public health for spraying and in bednets. Salivary glands of vectors are the first target organ for human-vector contact during biting and parasite-vector contact prior to parasite development in the mosquito midguts. The salivary glands secrete anti-haemostatic, anti-inflammatory biologically active molecules to facilitate blood feeding from the host and also inadvertently inject malaria parasites into the vertebrate host. The Anopheles stephensi mosquito, an urban vector of malaria to both human and rodent species has been identified as a reference laboratory model to study mosquito—parasite interactions. In this study, we adopted a conventional proteomic approach of 2D-electrophoresis coupled with MALDI-TOF mass spectrometry and bioinformatics to identify putative differentially expressed annotated functional salivary proteins between An. stephensi susceptible and multiresistant strains with same genetic background. Our results show 2D gel profile and MALDI-TOF comparisons that identified 31 differentially expressed putative modulated proteins in deltamethrin/DDT resistant strains of An. stephensi. Among these 15 proteins were found to be upregulated and 16 proteins were downregulated. Our studies interpret that An. stephensi (multiresistant) caused an upregulated expression of proteins and enzymes like cytochrome 450, short chain dehyrdogenase reductase, phosphodiesterase etc that may have an impact in insecticide resistance and xenobiotic detoxification. Our study elucidates a proteomic response of salivary glands differentially regulated proteins in response to insecticide resistance development which include structural, redox and regulatory enzymes of several pathways. These identified proteins may play a role in regulating mosquito biting behavior patterns and may have implications in the development of malaria parasites in resistant mosquitoes during parasite transmission.
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Affiliation(s)
- Sonam Vijay
- Protein Biochemistry and Structural Biology Laboratory, National Institute of Malaria Research (ICMR), Sector-8, Dwarka, New Delhi, India
| | - Ritu Rawal
- Protein Biochemistry and Structural Biology Laboratory, National Institute of Malaria Research (ICMR), Sector-8, Dwarka, New Delhi, India
| | - Kavita Kadian
- Protein Biochemistry and Structural Biology Laboratory, National Institute of Malaria Research (ICMR), Sector-8, Dwarka, New Delhi, India
| | - Kamaraju Raghavendra
- Insecticide Resistance Laboratory, National Institute of Malaria Research (ICMR), Sector-8, Dwarka, New Delhi, India
| | - Arun Sharma
- Protein Biochemistry and Structural Biology Laboratory, National Institute of Malaria Research (ICMR), Sector-8, Dwarka, New Delhi, India
- * E-mail:
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Rochael NC, Lima LG, Oliveira SMPD, Barcinski MA, Saraiva EM, Monteiro RQ, Pinto-da-Silva LH. Leishmania amazonensis exhibits phosphatidylserine-dependent procoagulant activity, a process that is counteracted by sandfly saliva. Mem Inst Oswaldo Cruz 2014; 108:679-85. [PMID: 24037188 PMCID: PMC3970692 DOI: 10.1590/0074-0276108062013002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 07/02/2013] [Indexed: 12/19/2022] Open
Abstract
Leishmania parasites expose phosphatidylserine (PS) on their
surface, a process that has been associated with regulation of host's immune
responses. In this study we demonstrate that PS exposure by metacyclic
promastigotes of Leishmania amazonensis favours blood
coagulation. L. amazonensis accelerates in vitro coagulation of
human plasma. In addition, L. amazonensis supports the assembly
of the prothrombinase complex, thus promoting thrombin formation. This process
was reversed by annexin V which blocks PS binding sites. During blood meal,
Lutzomyia longipalpis sandfly inject saliva in the bite
site, which has a series of pharmacologically active compounds that inhibit
blood coagulation. Since saliva and parasites are co-injected in the host during
natural transmission, we evaluated the anticoagulant properties of sandfly
saliva in counteracting the procoagulant activity of L.
amazonensis . Lu. longipalpis saliva reverses
plasma clotting promoted by promastigotes. It also inhibits thrombin formation
by the prothrombinase complex assembled either in phosphatidylcholine (PC)/PS
vesicles or in L. amazonensis . Sandfly saliva inhibits factor
X activation by the intrinsic tenase complex assembled on PC/PS vesicles and
blocks factor Xa catalytic activity. Altogether our results show that metacyclic
promastigotes of L. amazonensis are procoagulant due to PS
exposure. Notably, this effect is efficiently counteracted by sandfly
saliva.
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Affiliation(s)
- Natalia Cadaxo Rochael
- Departamento de Imunologia, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de JaneiroRJ, Brasil
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Aslam S, Francis PG, Rao BHS, Ummar M, Issac JK, Nair RB. A double blind study on the efficacy of local application of hemocoagulase solution in wound healing. J Contemp Dent Pract 2013; 14:394-400. [PMID: 24171979 DOI: 10.5005/jp-journals-10024-1334] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
AIM The present double blind study has been designed to evaluate the efficacy of local application of hemocoagulase solution as compared to a placebo in wound healing following dental extraction. MATERIALS AND METHODS A total of 20 patients who required dental extraction for orthodontic intervention were included. The hemocoagulase solution and a placebo were locally applied to the extraction sockets and the efficacy of the solution in terms of bleeding control, anti-inflammatory responses, its antiseptic properties and efficacy in wound healing were evaluated. RESULTS The mean time required to achieve hemostasis was found to be 1.37 minutes in side A (test) and 2.33 minutes in side B (control) indicating that side A achieved faster hemostasis when compared to side B. At the 6th hour postoperatively, bleeding was not evident on either sides, and the amount of pain in side A was found to be less compared to side B. The number of RBCs, polymorphs, chronic inflammatory cells were not different in both the groups, whereas at 3rd postoperative day epithelial cells were greater in side A (test) compared to side B (control). Biopsy reports on the 12th postoperative day indicated that the number of fibroblasts, epithelial cells, collagen count was found to be greater in side A (test) compared to side B (control). CONCLUSION The topical hemocoagulase solution may be advocated in the field of oral and maxillofacial surgery, as a hemostatic agent and promoter of wound healing. However, further studies, with large number of cases and different clinical situations should be considered to authenticate the efficacy of this hemocoagulase solution in the practice of oral and maxillofacial surgery. CLINICAL SIGNIFICANCE Wound healing plays an important role in the success of any surgical procedure, such as extractions, and the hemocoagulase system may act as a hemostatic agent and a promoter of wound healing.
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Affiliation(s)
- Sachin Aslam
- Reader, Department of Oral Surgery, MES Dental College, Malappuram Kerala, India, e-mail:
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Sidhu PS, Mosier PD, Zhou Q, Desai UR. On scaffold hopping: challenges in the discovery of sulfated small molecules as mimetics of glycosaminoglycans. Bioorg Med Chem Lett 2012; 23:355-9. [PMID: 23164711 DOI: 10.1016/j.bmcl.2012.10.079] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2012] [Revised: 10/04/2012] [Accepted: 10/15/2012] [Indexed: 01/25/2023]
Abstract
The design of sulfated, small, nonsaccharide molecules as modulators of proteins is still in its infancy as standard drug discovery tools such as library of diverse sulfated molecules and in silico docking and scoring protocol have not been firmly established. Databases, such as ZINC, contain too few sulfate-containing nonsaccharide molecules, which severely limits the identification of new hits. Lack of a generally applicable protocol for scaffold hopping limits the development of sulfated small molecules as synthetic mimetics of the highly sulfated glycosaminoglycans. We explored a sequential ligand-based (LBVS) and structure-based virtual screening (SBVS) approach starting from our initial discovery of monosulfated benzofurans to discover alternative scaffolds as allosteric modulators of thrombin, a key coagulation enzyme. Screening the ZINC database containing nearly 1 million nonsulfated small molecules using a pharmacophore developed from the parent sulfated benzofurans followed by a genetic algorithm-based dual-filter docking and scoring screening identified a group of 10 promising hits, of which three top-scoring hits were synthesized. Each was found to selectively inhibit human alpha-thrombin suggesting the possibility of this approach for scaffold hopping. Michaelis-Menten kinetics showed allosteric inhibition mechanism for the best molecule and human plasma studies confirmed good anticoagulation potential as expected. Our simple sequential LBVS and SBVS approach is likely to be useful as a general strategy for identification of sulfated small molecules hits as modulators of glycosaminoglycan-protein interactions.
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Affiliation(s)
- Preetpal S Sidhu
- Department of Medicinal Chemistry and Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, VA 23219, United States
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Allosteric activation of human α-thrombin through exosite 2 by suramin analogs. Arch Biochem Biophys 2012; 520:36-41. [DOI: 10.1016/j.abb.2012.02.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 02/01/2012] [Accepted: 02/01/2012] [Indexed: 11/22/2022]
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Sidhu PS, Liang A, Mehta AY, Abdel Aziz MH, Zhou Q, Desai UR. Rational design of potent, small, synthetic allosteric inhibitors of thrombin. J Med Chem 2011; 54:5522-31. [PMID: 21714536 DOI: 10.1021/jm2005767] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Thrombin is a key enzyme targeted by the majority of current anticoagulants that are direct inhibitors. Allosteric inhibition of thrombin may offer a major advantage of finely tuned regulation. We present here sulfated benzofurans as the first examples of potent, small allosteric inhibitors of thrombin. A sulfated benzofuran library of 15 sulfated monomers and 13 sulfated dimers with different charged, polar, and hydrophobic substituents was studied in this work. Synthesis of the sulfated benzofurans was achieved through a multiple step, highly branched strategy, which culminated with microwave-assisted chemical sulfation. Of the 28 potential inhibitors, 11 exhibited reasonable inhibition of human α-thrombin at pH 7.4. Structure-activity relationship analysis indicated that sulfation at the 5-position of the benzofuran scaffold was essential for targeting thrombin. A tert-butyl 5-sulfated benzofuran derivative was found to be the most potent thrombin inhibitor with an IC(50) of 7.3 μM under physiologically relevant conditions. Michaelis-Menten studies showed an allosteric inhibition phenomenon. Plasma clotting assays indicate that the sulfated benzofurans prolong both the activated partial thromboplastin time and prothrombin time. Overall, this work puts forward sulfated benzofurans as the first small, synthetic molecules as powerful lead compounds for the design of a new class of allosteric inhibitors of thrombin.
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Affiliation(s)
- Preetpal Singh Sidhu
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, Virginia 23219, United States
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Das S, Radtke A, Choi YJ, Mendes AM, Valenzuela JG, Dimopoulos G. Transcriptomic and functional analysis of the Anopheles gambiae salivary gland in relation to blood feeding. BMC Genomics 2010; 11:566. [PMID: 20946652 PMCID: PMC3091715 DOI: 10.1186/1471-2164-11-566] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2010] [Accepted: 10/14/2010] [Indexed: 02/05/2023] Open
Abstract
Background The Anopheles gambiae salivary glands play a major role in malaria transmission and express a variety of bioactive components that facilitate blood-feeding by preventing platelet aggregation, blood clotting, vasodilatation, and inflammatory and other reactions at the probing site on the vertebrate host. Results We have performed a global transcriptome analysis of the A. gambiae salivary gland response to blood-feeding, to identify candidate genes that are involved in hematophagy. A total of 4,978 genes were found to be transcribed in this tissue. A comparison of salivary gland transcriptomes prior to and after blood-feeding identified 52 and 41 transcripts that were significantly up-regulated and down-regulated, respectively. Ten genes were further selected to assess their role in the blood-feeding process using RNAi-mediated gene silencing methodology. Depletion of the salivary gland genes encoding D7L2, anophelin, peroxidase, the SG2 precursor, and a 5'nucleotidase gene significantly increased probing time of A. gambiae mosquitoes and thereby their capacity to blood-feed. Conclusions The salivary gland transcriptome comprises approximately 38% of the total mosquito transcriptome and a small proportion of it is dynamically changing already at two hours in response to blood feeding. A better understanding of the salivary gland transcriptome and its function can contribute to the development of pathogen transmission control strategies and the identification of medically relevant bioactive compounds.
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Affiliation(s)
- Suchismita Das
- W Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, 615 N Wolfe Street, Baltimore, MD 21205-2179, USA
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Ricci CG, Pinto AFM, Berger M, Termignoni C. A thrombin inhibitor from the gut of Boophilus microplus ticks. EXPERIMENTAL & APPLIED ACAROLOGY 2007; 42:291-300. [PMID: 17710557 DOI: 10.1007/s10493-007-9097-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2006] [Accepted: 08/07/2007] [Indexed: 05/16/2023]
Abstract
A thrombin inhibitor was identified for the first time in the gut of the cattle tick Boophilus microplus. Here we present the partial purification and characterization of this new molecule, which was purified from the gut extract by three chromatographic steps: ion-exchange, gel filtration and affinity chromatography in a thrombin-Sepharose resin. In SDS-PAGE the inhibitor showed an apparent molecular mass of circa 26 kDa, which is different from the two thrombin inhibitors present in the saliva of this tick. The new inhibitor delays bovine plasma clotting time and inhibits both thrombin induced fibrinogen clotting and thrombin induced platelet aggregation. However, it does not interfere with thrombin amidolytic activity upon a small substrate (H-D-Phe-Pip-Arg-para-nitroanilide), which does not require binding to thrombin exosites. Therefore, the inhibitor does not block thrombin active site, although it must interfere with one of the thrombin exosites. B. microplus gut thrombin inhibitor (BmGTI) is also capable of enhancing activated protein C (APC) activity upon its specific substrate (H-D-Glu-Pro-Arg-para-nitroanilide), an activity never described before among B. microplus molecules.
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Affiliation(s)
- Clarisse Gravina Ricci
- Centro de Biotecnologia da Universidade Federal do Rio Grande do Sul, 15005, Porto Alegre, 91501-970, Brazil
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Ciprandi A, de Oliveira SK, Masuda A, Horn F, Termignoni C. Boophilus microplus: Its saliva contains microphilin, a small thrombin inhibitor. Exp Parasitol 2006; 114:40-6. [PMID: 16600217 DOI: 10.1016/j.exppara.2006.02.010] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2005] [Revised: 02/08/2006] [Accepted: 02/09/2006] [Indexed: 10/24/2022]
Abstract
Saliva of the cattle tick Boophilus microplus contains two thrombin inhibitors, BmAP and microphilin. This work presents the purification and characterization of microphilin. It was purified from the saliva by gel filtration, ultrafiltration through a 3 kDa cut-off membrane and affinity chromatography in a thrombin-Sepharose column. Analysis by mass spectrometry showed a molecular mass of 1770 Da. Microphilin is the smallest salivary thrombin inhibitor peptide known to date. It inhibits fibrinocoagulation and thrombin-induced platelet aggregation with an IC(50) of 5.5 microM, is temperature resistant and its inhibitory activity was abolished by protease K treatment. Microphilin did not inhibit the amidolytic activity of the enzyme upon a small chromogenic substrate, but inhibited the hydrolysis of a substrate that binds both catalytic site and exosite I. Therefore, we propose that microphilin blocks thrombin at exosite I.
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Affiliation(s)
- Alessandra Ciprandi
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, P.O. Box 15005, 91501-970 Porto Alegre, RS, Brazil
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