Altered Neural Function in a Human 3D Culture Model of AD
In this project, we will further develop and characterize a human “Alzheimer’s disease in a dish” model based on a unique three-dimensional (3D) human neural progenitor cell culture technique. In our recent publication and preliminary studies, we have shown that a human 3D cell culture model can recapitulate key events in Alzheimer’s disease (AD), which has not been feasible in AD animal models. Here, we will investigate mechanisms underlying these pathogenic events, including amyloid beta (Aβ), tau tangles, abnormal neuronal activity, synaptic/cellular injury, and potentially, neurodegeneration. If successful, our studies will provide a novel and validated platform for basic mechanistic studies and drug screening in a human brain-like environment, which could largely accelerate AD drug discovery.
We are developing a three-dimensional (3D) human neural cell culture model of Alzheimer’s disease (AD) for basic mechanical studies and drug discovery. Recently, we showed that genetically engineered human neural stem cells combined with a unique 3D culture system we developed, can recapitulate key pathogenic events in AD. Using these 3D human cellular models, we are studying the molecular mechanisms responsible for how β-amyloid (Aβ) accumulation leads to altered neuronal activity, synaptic injuries and eventually neuronal death, in a human brain-like environment. The overarching goal of this study is to establish human cellular AD models that recapitulate the functional deficits caused in patients by Aβ and tau pathologies, for disease modelling and drug discovery.
Key Details. Alzheimer's disease (AD) has become the sixth leading cause of death in the United States, and the number of patients is expected to increase dramatically over the next decade. However, there is no clear therapeutic option at this moment. AD transgenic mice, which have proven very useful for testing candidate AD drugs before human clinical trials, have not been able, however, to fully replicate key parts of the AD pathogenic cascades, including clear tau tangle pathology and neurodegeneration. This might explain why many successful treatments in mice have not led to similar success in humans.
Recently, we produced a novel three-dimensional (3D) human neural cell culture model of AD using genetically engineered human neural stem cells (Choi et al., 2014; Kim et al., 2015). Using this model, we showed, for the first time, that excess accumulation of β-amyloid (Aβ) is sufficient to induce robust tau tangle pathology. While we have successfully recapitulated two major pathological markers of AD, we have not fully characterized the neuronal deficits, including synaptic dysfunction and altered neuronal activity that could contribute to increased vulnerability to neuronal death. Therefore, we will now investigate the presence and degree of altered neural activity in 3D-cultured human neural AD models (Aim 1), and the synaptic/cellular injuries that occur in this model (Aim 2), while exploring the molecular mechanisms underlying neural/synaptic disease phenotypes (Aim 3). The overarching goal of this study is to establish human cellular AD models that closely recapitulate the functional deficits caused in patients by Aβ and tau pathologies, for basic mechanistic studies, disease modelling, and AD drug discovery. Since no AD mouse model of Aβ deposition leads to tangles and neurodegeneration, both of which are critical aspects of the disease, the human neural cell culture model could begin to serve as a disease–relevant drug discovery platform for AD.
About the Researcher
Dr. Doo Yeon Kim has been studying pathogenic mechanisms of Alzheimer’s disease (AD) for more than 15 years. He was born in South Korea, where he obtained his PhD degree (from Korea Advanced Institute of Science and Technology in Daejon, South Korea). In 2001, he moved to the United States to continue his studies in Dr. Dora Kovacs’ laboratory at Massachusetts General Hospital (MGH) in Boston. In 2009, he was appointed assistant professor of neurology at MGH/Harvard Medical School (HMS). Dr. Kim explores physiological and pathological functions of BACE1 [Beta-secretase 1, also known as beta-site amyloid precursor protein cleaving enzyme 1] and presenilin/γ-secretase. Both BACE1 and presenilin/γ-secretase are key enzymes that regulate generation of β-amyloid, major pathogenic molecules associated with AD. Recently, Dr. Kim’s laboratory developed a human stem cell culture model of AD by cultivating genetically modified human neural stem cells in a three-dimensional cell culture system. With this system, they were able to recapitulate key pathogenic events of AD pathology, including β-amyloid plaques and neurofibrillary tangles for the first time. This unique human neural cell culture model can be used for large-scale high-throughput screening for novel therapeutic targets, which has not been feasible in the current AD mouse models. This work has been listed as one of “10 Breakthrough Technologies 2015” by MIT Technology Review. Dr. Kim received The John Douglas French Foundation Fellowship Award and recently, the 2015 Smithsonian American Ingenuity Award.
The co-principal investigator, Dr. Clifford J. Woolf, works on pain and the regeneration and degeneration of the nervous system, with a particular focus on neurological disease modeling and drug screening in patient induced pluripotent stem (iPS) cell-derived neurons. He was born in South Africa, where he earned his MD and PhD degrees. He moved to London in 1979, and became professor of neurobiology at University College London. In 1997, he was recruited by the MGH and HMS to serve as the first Richard J. Kitz Professor of Anesthesiology Research at HMS. In 2007, he was appointed principal faculty member of the Harvard Stem Cell Institute, and in 2010 was named director of the F. M. Kirby Neurobiology Center at Boston Children’s Hospital, and also became professor of neurology and neurobiology at HMS. Dr. Woolf is deputy director of the Intellectual Developmental Disability Disorders Center at Boston Children’s Hospital and co-director of the neuroscience program of the Harvard Stem Cell Institute. Over his career Dr. Woolf has received many honors and prizes. Most recently he was awarded the Kerr award from the American Pain Society, a Founders Award from the American Academy of Pain Medicine and became an honorary fellow of the Irish College of Anesthetists (2015). He was a Thompson Reuters Highly Cited Researcher in 2014, was awarded the Magnes medal in Israel (2013) and was selected to deliver the FE Bennett Memorial Lecture by the American Neurological Association (2012). He was awarded a Javits Award from the National Institute of Neurological Diseases and Stroke (NINDS) at the National Institutes of Health (2011); delivered the Schmidt lecture at the Massachusetts Institute of Technology (2011) and the Bonica Lecture for the International Society of the Study of Pain (2010); was visiting professor at Columbia University (2009); and received the Wall Medal from the Royal College of Anesthetists in the UK (2009). He has founded three companies and holds 17 patents.
During my early scientific career, I was deeply intrigued by the complexity of brains. It is fascinating to me that many brain cells communicate with each other through complex networks in a concerted manner. In my opinion, understanding brain networks is essential to finding better therapeutic options for patients with Alzheimer’s disease (AD).
After finishing my post-doctoral training and becoming a junior investigator, I was quite excited to jump start the projects that I had been planning. Making a 3D human neural cell culture model of AD was one of them. I observed that many exciting ideas, which may revolutionize Alzheimer’s therapy, could not go further due to lack of easy and reliable cellular model systems that can closely mimic human brains with AD. The problem, I soon realized, is that it is not easy to get funding for these projects. Government funding generally requires lots of preliminary data, and for a junior principal investigator P.I.s like me, it is hard to secure enough resources for that. Private funding sources, like the BrightFocus grant, were instrumental in filling these gaps.
Being awarded this BrightFocus grant is another opportunity for me to push forward these projects, which could have not been possible due to budget limitations. I really appreciate the BrightFocus Foundation and the generous donors for their support of our studies.
First published on: July 26, 2016
Last modified on: January 30, 2020