Alzheimer?s disease (AD) is a neurodegenerative brain disorder, ranking as the 6th leading cause of death in the United States and affecting approximately 5.5 million Americans. While characterized by an accumulation of extracellular beta-amyloid (A?) plaques, many processes associated with disease onset and progression remain poorly understood. While a key hallmark of AD, there is a high failure rate of clinical trials in AD drug development focusing on A? alone. Recently, efforts have begun to interrogate synergistic effects of other comorbidities with AD. As a result, there is a significant need for experimental platforms to investigate effects of systemic abnormalities and other chronic conditions that contribute to AD progression. Reduced cerebral blood flow and glucose metabolism, often related to cardiovascular disease (CVD), are often found in patients with AD, motivating our effort to adapt micro-scale tissue engineering platforms to investigate the role of localized foci of hypoxia on cellular hallmarks of AD. Efforts associated with the parent grant (R01 CA197488) for this supplement have recently developed hydrogel platforms to explore the role of matrix transitions and cell-cell interactions on the invasive spreading and drug resistance in glioblastoma, the most common and lethal form of brain cancer. The overall goal of this supplement is to adapt these existing biomaterial tools to elucidate the role of mechanisms associated to systemic abnormalities (CVD) in A? metabolism and find new biomarkers that predict the development of the disease. This innovative approach will consider the modification of the microenvironment to mimic pathological conditions of AD, such as hypoxia, with subsequent toxicity evaluated via A? deposition and changes in the differentiation patterns of neural cell populations. The reason why A? accumulates is unclear, but the understanding of its metabolism and elimination will be crucial to the development of therapeutic targets to treat AD. This project will first develop a suite of miniaturized biomaterials relevant to the native in vivo environment in the brain, including recapitulating the native stiffness <1 kPa and incorporating relevant extracellular matrix components relevant to the neural microenvironment (Aim 1). Reproducibility will be defined by analyzing neuronal health and connectivity and be used to will identify appropriate biophysical properties for long term culture of brain cells in three-dimensional structures. This project will then elucidate the effects of hypoxia on A? metabolism in patient-derived human induced pluripotent stem cells (hiPSCs) from patients with and without AD (Aim 2). Microfluidic techniques to generate miniaturized hydrogel environments allow us to replicate relevant 3D tissue architectures, notably regions of local hypoxic foci and gradients of hypoxia-associated tissue responses, in our neural cultures. Taken together, the results developed in this project may provide deeper insights into the role of systemic abnormalities on the onset and progression of AD and may aid in the development of novel therapeutics to treat AD.
Alzheimer?s disease is a neurodegenerative disease characterized by an accumulation of extracellular beta- amyloid (A?) plaques that can be exacerbated by chronic conditions such as cardiovascular disease induced hypoxia. This project will develop and characterize a three-dimensional hydrogel platform to investigate the influence of matrix microenvironment and hypoxia on A? metabolism. We will establish tissue engineering tools to support neural stem cell differentiation into neurons, astrocytes, and oligodendrocytes, enable reproducible formation of neural networks, and trace resultant shifts in A? metabolism underlying Alzheimer?s progression.
