Alzheimer?s disease (AD) is a progressive neurodegenerative disorder and is characterized neuropathologically by amyloid plaques and neurofibrillary tangles. The patients with AD have morphological and functional alterations of the cerebral circulation, resulting in abnormalities of morphological cerebral micro-vessels and reduced cerebral blood flow (CBF). Mesenchymal stem cells (MSCs) are capable of interacting with resident cells in the brain to stimulate the production of neurotrophins that can potentialize neuroregeneration and neurologic recovery. It has been reported that the beneficial effects of stem cells are mostly due to secreted paracrine factors, many of which are in form of extracellular vesicles (EVs), including exosomes (EXO), and microvesicles. It has been demonstrated that EXO secreted from stem cells have the ability to reduce brain ?- amyloid. Moreover, the therapeutic potential of EXO can be modified through pre-conditioning or genetic manipulation of their parent stem cells. GATA-4, a cardiac transcription factor, has been demonstrated to promote angiogenesis and extend cells survival. We have successfully transduced GATA-4 into bone marrow MSCs and isolated EXO from these cells (ExoGATA-4). Our parent R01 grant (PIs: Drs. Meifeng Xu and Min Liu) aims to investigate whether EXO derived from MSCs overexpressing GATA-4 (ExoGATA-4) can deliver specific molecules in a timely fashion to promote angiogenesis and regenerate ischemic myocardium through intravenous (iv) administration. That project uses well-established state-of-the-art technologies in proposed studies. In this one-year supplemental application, we will apply similar techniques to test our hypothesis that ExoGATA-4 iv administrated can improve cognitive deficits by reducing aggregation of ?-amyloid in neuronal cells and promoting angiogenesis in AD transgenic mice. Our preliminary study has indicated that EXO derived from bone marrow MSCs can enter brain specific regions through blood brain barrier following iv administration. EXO increase brain endothelial cell proliferation and protect them against hypoxic injury. Moreover, we have found that the effectiveness of ExoGATA-4 on angiogenesis is more efficient in promoting angiogenesis than EXO derived from control MSCs.
The specific aim of this supplemental application is to characterize the impact of therapeutic strategies of ExoGATA-4 on promoting angiogenesis in brain and improving cognitive deficits associated with AD. The proposed research is highly significant and innovative because it will advance our understanding of the roles of EXO as a novel approach for AD therapeutic treatment. Furthermore, the highly translational nature of the project derives from its potential in clinical application.
The overall goal of this one-year project is to determine whether small vesicles derived from the genome- edited stem cells can improve cognitive deficits associated with Alzheimer?s disease via increasing brain blood flow. The success of the proposed project may lead to the development of a novel therapeutic strategy and facilitate clinical translation of small vesicles derived from stem cells to Alzheimer?s disease therapeutic treatment.