Schistosomes are parasitic flatworms that cause a chronic, debilitating disease afflicting over 200 million people in over 70 countries. The parasite live for years, sometimes decades, in what should be a very hostile environment - the blood of vertebrates - yet they appear to elicit little if any overt reaction from the host's hemostatic system. We hypothesize that proteins at the host-interactive surface, identified in the previous funding cycle, are central to the parasites ability to impede host hemostasis. In this competing renewal, we propose to test several key hypotheses concerning: 1) the role of tegumental ecto-enzymes in blocking platelet activation and aggregation, 2) the ability of tegumental protease(s) to cleave key coagulation proteins, and 3) the role of tegumental plasminogen-binding proteins in activating plasmin and promoting thrombolysis. These studies will yield significant new information on the molecular mechanisms used by schistosomes to blunt the host thrombotic response. In addition, the work may identify tegumental proteins critical for parasite survival leading to subsequent screens to discover potential schistosome-killing drugs that inhibit these molecules and/or to trials testing their vaccine potential. In this way, our planned experiments have the potential to reveal novel and valid targets, as well as new treatments, for intervention in a parasite that remains a widespread and major cause of human disease. Additionally, given wide interest in understanding the mechanisms governing coagulation control, knowing how schistosomes regulate this process will be of keen interest beyond the field of eukaryotic pathogen research.

Public Health Relevance

Schistosomes are parasite worms that live in the blood streams of over 200 million people in more than 70 countries. These parasites are a major cause of death and disability worldwide. The worms have remarkable properties that allow them live inside people for many years. These properties include an ability to impede blood clotting reactions. By understanding more precisely how the parasites achieve these ends, we aim to devise new strategies to kill the worms.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
2R01AI056273-11
Application #
8964247
Study Section
Pathogenic Eukaryotes Study Section (PTHE)
Program Officer
Wali, Tonu M
Project Start
2003-06-01
Project End
2020-05-31
Budget Start
2015-06-01
Budget End
2016-05-31
Support Year
11
Fiscal Year
2015
Total Cost
Indirect Cost
Name
Tufts University
Department
Veterinary Sciences
Type
Schools of Veterinary Medicine
DUNS #
039318308
City
Boston
State
MA
Country
United States
Zip Code
Elzoheiry, Manal; Da'dara, Akram A; Bhardwaj, Rita et al. (2018) Intravascular Schistosoma mansoni Cleave the Host Immune and Hemostatic Signaling Molecule Sphingosine-1-Phosphate via Tegumental Alkaline Phosphatase. Front Immunol 9:1746
Wang, Qiang; Da'dara, Akram A; Skelly, Patrick J (2018) The blood fluke Schistosoma mansoni cleaves the coagulation protein high molecular weight kininogen (HK) but does not generate the vasodilator bradykinin. Parasit Vectors 11:182
Wang, Qiang; Da'dara, Akram A; Skelly, Patrick J (2017) The human blood parasite Schistosoma mansoni expresses extracellular tegumental calpains that cleave the blood clotting protein fibronectin. Sci Rep 7:12912
Krautz-Peterson, Greice; Debatis, Michelle; Tremblay, Jacqueline M et al. (2017) Schistosoma mansoni Infection of Mice, Rats and Humans Elicits a Strong Antibody Response to a Limited Number of Reduction-Sensitive Epitopes on Five Major Tegumental Membrane Proteins. PLoS Negl Trop Dis 11:e0005306
Da'dara, Akram A; Siddons, Giles; Icaza, Melissa et al. (2017) How schistosomes alter the human serum proteome. Mol Biochem Parasitol 215:40-46
Da'dara, Akram A; de Laforcade, Armelle M; Skelly, Patrick J (2016) The impact of schistosomes and schistosomiasis on murine blood coagulation and fibrinolysis as determined by thromboelastography (TEG). J Thromb Thrombolysis 41:671-7
Figueiredo, Barbara C; Da'dara, Akram A; Oliveira, Sergio C et al. (2015) Schistosomes Enhance Plasminogen Activation: The Role of Tegumental Enolase. PLoS Pathog 11:e1005335
Da'dara, Akram A; Skelly, Patrick J (2015) Gene suppression in schistosomes using RNAi. Methods Mol Biol 1201:143-64
Figueiredo, Barbara C; Assis, Natan R G; Morais, Suellen B et al. (2014) Schistosome syntenin partially protects vaccinated mice against Schistosoma mansoni infection. PLoS Negl Trop Dis 8:e3107
Da'dara, Akram A; Krautz-Peterson, Greice (2014) New insights into the reaction of Schistosoma mansoni cercaria to the human complement system. Parasitol Res 113:3685-96

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