Stem cell based small molecule therapy for Alzheimer’s disease

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.

Introduction: Over 6 million people in the US suffer from Alzheimer’s disease (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 to identify neurogenic compounds, we have shown that it is now be possible to identify and tailor drugs for therapeutic use in AD. This was the overall goal of this application, and to date we have made outstanding progress, making a drug that is both neurogenic for human cells and has therapeutic efficacy in a rigorous mouse model of AD. Year 2 Progress: Using a novel drug discovery paradigm based upon human stem cell derived nerve precursor cells, we have made a very potent drug called CAD-31. CAD-31 potently stimulates neurogenesis in human cells in culture and in mice, and prevents nerve cell death in cell culture models of toxicities associated with old age and AD. Very few, if any, drugs or drug candidates are both neuroprotective and neurogenic, particularly in animals. In the first year of this project, we harnessed the power of hESCs and medicinal chemistry to develop CAD-31. All of the Year 1 milestones were met. In Year 2 we completed all of the required pharmacokinetics and safety studies on the six best compounds synthesized in Year 1. Of those six, one compound, CAD-31, was the best in terms of medicinal chemical, pharmacokinetic, neuroprotective and neurogenic properties. This compound underwent extensive testing for safety and passed with flying colors. It was then put into an AD mouse model where it stimulated neurogenesis, prevented behavioral deficits and some of the disease pathology. All Year 2 milestones were completed. In Year 3 of the project we will determine if CAD-31 is able to reverse AD symptoms in old AD mice that already have the disease. This is the most clinically relevant model of AD since therapies can only be initiated once the disease is identified. This work has produced a novel AD drug candidate that is developed based upon a set of assays never before used by pharmaceutical companies. It 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 drug discovery for the treatment of neurodegenerative disease.

Introduction: Over 6 million people in the US suffer from Alzheimer’s disease (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 to identify neurogenic compounds, we have shown that it is now be possible to identify and tailor drugs for therapeutic use in AD. This was the overall goal of this application, and to date we have made outstanding progress, making a drug that is both neurogenic for human cells and has therapeutic efficacy in a rigorous mouse model of AD. Using a novel drug discovery paradigm based upon human stem-cell derived nerve-precursor cells, we have made a very potent drug called CAD-31. CAD-31 potently stimulates neurogenesis in human cells in culture and in mice, and prevents nerve cell death in cell culture models of toxicities associated with old age and AD. Very few, if any, drugs or drug candidates are both neuroprotective and neurogenic, particularly in animals. We harnessed the power of hESCs and medicinal chemistry to develop CAD-31. We completed extensive pharmacokinetic and safety studies on the six best of over 200 compounds that were synthesized. Of those six, one compound, CAD-31, was the best in terms of medicinal chemical, pharmacokinetic, neuroprotective and neurogenic properties. This compound underwent extensive testing for safety and passed with flying colors. It was then put into an AD mouse model where it stimulated neurogenesis, prevented behavioral deficits and some of the disease pathology. Finally, it was determined that CAD-31 is able to reverse AD symptoms in old AD mice that already have the disease. This is the most clinically relevant model of AD since therapies can only be initiated once the disease is identified. In summary, this work has produced a novel AD drug candidate that is developed based upon a set of assays never before used by pharmaceutical companies. It 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 drug discovery for the treatment of neurodegenerative disease.