Stroke neuroprotection with a recombinant fusion protein

DESCRIPTION (provided by applicant): Approximately 800,000 persons in the U.S. suffer an acute stroke each year. There presently is no neuroprotective agent that can be given to patients with acute stroke, and stroke is the third leading cause of death. The costs for rehabilitation of patients that survive a stroke are greater than $40 billion per year in the U.S. The reason that an effective neuroprotective drug has not been developed so far, despite intensive efforts in the pharmaceutical industry, is that most of the drugs do not cross the blood-brain barrier (BBB). Neurotrophins are potential large molecule neuroprotectives but these, too, do not cross the BBB. The present research plan aims at a merger of neurotrophin drug discovery and BBB drug targeting technology, so that a recombinant neurotrophin can be re-formulated as a genetically engineered fusion protein to enable transport of the neurotrophin through the BBB in vivo following delayed intravenous administration in humans. Such a drug will cause neuroprotection in stroke patients following intravenous administration, because the neuroprotective agent will have been specifically designed to cross the BBB. This work will prepare a genetically engineered fusion protein wherein the neurotrophin variant is fused to a targeting ligand that undergoes receptor-mediated transport across the BBB in vivo. This BBB transport vector has been previously genetically engineered to enable use in humans without immunological reaction. The fusion protein will be a bi-functional molecule that not only crosses the BBB, but also binds to the specific neurotrophin receptor on neurons to cause neuronal neuroprotection. In phase I, an expression vector was engineered for permanent transfection of cells. Immunocytochemistry and Western blotting demonstrated expression of the fusion protein by the permanently transfected cells. The phase II work will produce a cell line secreting high levels of the fusion protein, and the production of this protein will be scaled up for manufacturing. The completion of the phase II work will enable the preparation of an IND to the FDA for testing of this novel neuroprotective agent in acute stroke in humans.