Introduction: Over 6 million people in the US suffer from AD. There are no drugs that prevent the death of nerve cells in AD, nor has any drug been identified that can stimulate their replacement. Even if nerve cells could be replaced, the toxic environment of the brain will kill them unless they are protected by a drug. Therefore, drugs that stimulate the generation of new neurons (neurogenesis) alone will not be effective; a drug with both neurogenic and neuroprotective properties is required. With the ability to use cells derived from human embryonic stem cells (hESCs) as a screen for neurogenic compounds, it should now be possible to identify and tailor drugs for therapeutic use in AD. This is the overall goal of this application.
Year One Progress: Using a novel drug discovery paradigm, we have made a very potent drug called J147 that is exceptionally effective in rodent models of AD and also stimulates neurogenesis in both young and very old mice. Very few, if any, drugs or drug candidates are both neuroprotective and neurogenic, particularly in old animals. In the first year of this application we harnessed the power of hESCs and medicinal chemistry to develop derivatives of J147 specifically tailored to stimulate neurogenesis and be neuroprotective in human cells. Using iterative chemistry, we synthesized over 200 new compounds, tested them for neurogenic properties in ES-derived neural precursor cells, assayed their ability to protect from the amyloid toxicity associated with AD, and determined their metabolic stability. All of the year one milestones we met and we now have the required minimum of six compounds to move into year two studies. In addition, we have made a good start on the work for year two in that some pharmacokinetics and safety studies has been completed.
This work will optimize the chances for its true therapeutic potential in AD, and presents a unique opportunity to expand the use of hESCs for the development of a therapeutic for a disease for which there is no cure. This work could lead to a paradigm shift in the treatment of neurodegenerative disease.