SBIR-STTR Award

The use of platelet transfusions has increased dramatically since 1980s, but a safe, long-term plateletstorage method remains missing. Current practice has platelets stored at 20 to 24¿C after preparation,which has a limited lifetime up to 5 days primarily due to concerns about bacterial contamination.Refrigerated storage reduces platelet life-span because it causes glycoprotein-Ib (GPIb) receptors tocluster on specific microdomains of the platelet membrane. Recognition of specific glycated/syalylatedresidues on clustered glycoproteins by macrophage b2 integrins and hepatocyte Ashwell-Morellreceptors results in platelet phagocytosis by the host and removal from circulation. Thus, prevention ofglycoprotein clustering represents a useful target for chemical intervention. Platelet glycoproteins areintimately associated with intracellular cytoskeleton. Their clustering depends on the formation of lipidraft in the platelet membrane which in turn depends on the dynamics of the highly regulated processesof actomyosin assembly/disassembly. Rho family GTPases, including RhoA, Rac1 and Cdc42, are aclass of GTP-binding enzymes that are central regulators of F-actin polymerization/depolymarization,and have been shown to control lipid raft formation and composition. Therefore, changes in RhoGTPase activities may influence platelet membrane lipid raft assembly and glycoprotein composition.Based on preliminary and published data, we hypothesize that reversible targeting of Rho familyGTPases by small molecule inhibitors can prevent cytoskeleton-dependent refrigeration storage lesionsin platelets and result in increased platelet survival. In this project, we will analyze the cytoskeletalfunctions and in vivo viability of murine and human platelets after refrigeration in the presence orabsence of various combinations of specific inhibitors for Cdc42, Rac1 and RhoA GTPases.Combination of cell biology, drug discovery and platelet analysis expertise as demonstrated by multipleco-publications of the co-PIs resulting in an innovative, outside-the-box method for intervention inplatelet storage technology. Chemical drug targeting of Rho GTPase activities through interference ofprotein-protein interaction is a revolutionary approach allowing for reversible inhibition of cytoskeletalrearrangements for which our group has pioneered and own the intellectual property licensed to P2DInc.

Thesaurus Terms:
Actins;Actomyosin;Authority;Autologous;Bacteria;Base;Biological Assay;Blood;Blood Banks;Blood Circulation;Blood Platelets;Boxing;Cells;Cellular Biology;Chemical Addition;Chemicals;Cold Temperature;Commercialization;Congenic;Cytoskeleton;Data;Development;Dna Sequence Rearrangement;Dreams;Drug Discovery;Drug Targeting;Electron Microscopy;Enzymes;Erythrocytes;Event;Excision;F-Actin;Family;Family Member;Glycoprotein Ib;Glycoproteins;Goals;Gtp Binding;Guanine;Guanosine Triphosphate;Guanosine Triphosphate Phosphohydrolases;Health;Hepatocyte;Hour;Human;Improved;In Vitro;In Vivo;Inhibitor/Antagonist;Innovation;Integrins;Intellectual Property;Intervention;Label;Lead;Lesion;Licensing;Lipids;Longevity;Macrophage;Malignant Neoplasms;Mediating;Member;Membrane;Membrane Glycoproteins;Membrane Lipids;Membrane Microdomains;Methods;Mus;Myosin Atpase;New Technology;Novel;Nucleotides;Patients;Phagocytosis;Platelet Count Measurement;Platelet Glycoproteins;Platelet Inhibitors;Platelet Preservation;Platelet Transfusion;Polymerization;Preparation;Prevent;Prevention;Process;Property Rights;Protein Protein Interaction;Publications;Publishing;Receptor;Receptor Activation;Recovery;Refrigeration;Rho;Rho Gtp-Binding Proteins;Signal Transduction;Small Molecule;Spectrin;Staining Method;Stains;Technology;Time;Transfusion;Trauma;Tubulin;Work;

The use of platelet transfusions has increased dramatically since 1980s, but a safe, long-term platelet storagemethod remains missing. Current practice has platelets stored at 20 to 24°C after preparation, which has alimited lifetime up to 5 days primarily due to concerns about bacterial contamination, because cold storage ofplatelets results in complex molecular lesions that are recognized by host macrophages and hepatocytecounterreceptors, leading to phagocytosis and clearance upon transfusion. In prior NIH SBIR phase 1 fundedstudies, we demonstrate functionally that murine, human and Rhesus-macaque washed platelets, when storedin refrigerated conditions for 7-14 days in the presence of a reversible RhoA GTPase inhibitor, G04, can fullymaintain function to a level like that of room-temperature stored platelets. We hypothesize that reversibleinhibition of RhoA via the G04 pharmacologic inhibitor can be translated to a new regimen for safe, cost-efficient,and fully functional long-term storage of platelets in refrigeration. This project will develop our product, the RhoAinhibitor S-G04, an enantiomer of G04, in a Platelet Additive Solution contained in a medically available bag, forhuman platelet cold storage up to 14 days. Based on a previous discussion with the US Food and DrugAdministration (FDA), we aim to assess the pharmacokinetics and ADME of S-G04 in our product and todetermine the GLP stability and safety of S-G04 in FDA IND-enabling studies. The deliverables will include anestablished safety and efficacy of this product in a commercially available platelet storage PAS/bag, and thatthis revolutionary technology can be available to all blood centers/hospitals needing PLT transfusion as a singleinventory, like that for plasma and red blood cell supplies.

Public Health Relevance Statement:
NARRATIVE Hematology/oncology and trauma patients with low platelet counts often require platelet transfusion, and this is crucial in the treatment of patients with cancer or hematologic diseases. The development of a method to prevent platelet damage upon refrigeration is a dream in blood banking and it would revolutionize the current method of platelet storage. The proposal intends to develop a method to store fully functional platelets by refrigeration and will move a novel regimen for platelet cold storage to FDA IND filing and commercialization.

Project Terms: