Whole document restricted, see Access Instructions file below for details of how to access the print copy. / Huntington’s disease [HD] is a debilitating adult onset inherited neurodegenerative disorder with primary degeneration in the striatum and widespread secondary degeneration throughout the brain. There are currently no clinical treatments to prevent onset, delay progression or replace lost neurons. Striatal cell transplantation strategies under clinical evaluation appear viable and effective for the treatment of HD. However, the future of regenerative medicine lies in developing renewable, expandable multipotent neural cell sources for transplantation. This Thesis has investigated a range of novel developments for enhancing the therapeutic potential of neural progenitor cell transplantation in a quinolinic acid [QA] lesion rat model of HD using two cell sources, adult neural progenitor cells and human embryonic stem cell [hESC] derived neural progenitor cells. Chapter Three identified a novel method for in vitro lithium priming of adult neural progenitor cells which enhances their neurogenic potential at the expense of glial formation. Chapter Four demonstrated that lithium priming of adult neural progenitor cells altered their phenotypic fate in vivo after transplantation, enhancing regional specific differentiation and efferent projection formation. The therapeutic potential of this strategy was demonstrated by accelerated acquisition of motor function benefits in the QA model. Chapter Five then demonstrated the ability for post transplantation environmental enrichment to modify therapeutic functional outcomes in the QA lesion model, and through lithium priming and enrichment demonstrated that adult neural progenitors are amenable to combinatorial interventions which can alter their phenotypic fate and enhance anatomical integration. Chapter Six investigated the in vivo effects of in vitro noggin priming of hESC derived neural progenitor cells and identified enhanced safety and neuronal differentiation in the QA lesioned striatum after noggin priming. Furthermore Chapter Seven provided evidence for functional reconstruction and therapeutic functional benefits from transplantation of noggin primed hESC derived neural progenitor cells and also highlighted the need for systematic evaluations of hESC derived transplants to optimise their safety in vivo. These results are beneficial in demonstrating the realistic therapeutic potential held by these two cell sources. They demonstrate how transient interventions can enhance therapeutic outcomes of neural progenitor cell transplantation for HD and have developed the understanding of neural progenitor cell transplantation as a therapeutic tool, bringing transplantation from different cell sources closer to eventual translation for HD sufferers.

Whole document restricted, see Access Instructions file below for details of how to access the print copy. / Huntington’s disease [HD] is a debilitating adult onset inherited neurodegenerative disorder with primary degeneration in the striatum and widespread secondary degeneration throughout the brain. There are currently no clinical treatments to prevent onset, delay progression or replace lost neurons. Striatal cell transplantation strategies under clinical evaluation appear viable and effective for the treatment of HD. However, the future of regenerative medicine lies in developing renewable, expandable multipotent neural cell sources for transplantation. This Thesis has investigated a range of novel developments for enhancing the therapeutic potential of neural progenitor cell transplantation in a quinolinic acid [QA] lesion rat model of HD using two cell sources, adult neural progenitor cells and human embryonic stem cell [hESC] derived neural progenitor cells. Chapter Three identified a novel method for in vitro lithium priming of adult neural progenitor cells which enhances their neurogenic potential at the expense of glial formation. Chapter Four demonstrated that lithium priming of adult neural progenitor cells altered their phenotypic fate in vivo after transplantation, enhancing regional specific differentiation and efferent projection formation. The therapeutic potential of this strategy was demonstrated by accelerated acquisition of motor function benefits in the QA model. Chapter Five then demonstrated the ability for post transplantation environmental enrichment to modify therapeutic functional outcomes in the QA lesion model, and through lithium priming and enrichment demonstrated that adult neural progenitors are amenable to combinatorial interventions which can alter their phenotypic fate and enhance anatomical integration. Chapter Six investigated the in vivo effects of in vitro noggin priming of hESC derived neural progenitor cells and identified enhanced safety and neuronal differentiation in the QA lesioned striatum after noggin priming. Furthermore Chapter Seven provided evidence for functional reconstruction and therapeutic functional benefits from transplantation of noggin primed hESC derived neural progenitor cells and also highlighted the need for systematic evaluations of hESC derived transplants to optimise their safety in vivo. These results are beneficial in demonstrating the realistic therapeutic potential held by these two cell sources. They demonstrate how transient interventions can enhance therapeutic outcomes of neural progenitor cell transplantation for HD and have developed the understanding of neural progenitor cell transplantation as a therapeutic tool, bringing transplantation from different cell sources closer to eventual translation for HD sufferers.

Whole document restricted, see Access Instructions file below for details of how to access the print copy. / Huntington’s disease [HD] is a debilitating adult onset inherited neurodegenerative disorder with primary degeneration in the striatum and widespread secondary degeneration throughout the brain. There are currently no clinical treatments to prevent onset, delay progression or replace lost neurons. Striatal cell transplantation strategies under clinical evaluation appear viable and effective for the treatment of HD. However, the future of regenerative medicine lies in developing renewable, expandable multipotent neural cell sources for transplantation. This Thesis has investigated a range of novel developments for enhancing the therapeutic potential of neural progenitor cell transplantation in a quinolinic acid [QA] lesion rat model of HD using two cell sources, adult neural progenitor cells and human embryonic stem cell [hESC] derived neural progenitor cells. Chapter Three identified a novel method for in vitro lithium priming of adult neural progenitor cells which enhances their neurogenic potential at the expense of glial formation. Chapter Four demonstrated that lithium priming of adult neural progenitor cells altered their phenotypic fate in vivo after transplantation, enhancing regional specific differentiation and efferent projection formation. The therapeutic potential of this strategy was demonstrated by accelerated acquisition of motor function benefits in the QA model. Chapter Five then demonstrated the ability for post transplantation environmental enrichment to modify therapeutic functional outcomes in the QA lesion model, and through lithium priming and enrichment demonstrated that adult neural progenitors are amenable to combinatorial interventions which can alter their phenotypic fate and enhance anatomical integration. Chapter Six investigated the in vivo effects of in vitro noggin priming of hESC derived neural progenitor cells and identified enhanced safety and neuronal differentiation in the QA lesioned striatum after noggin priming. Furthermore Chapter Seven provided evidence for functional reconstruction and therapeutic functional benefits from transplantation of noggin primed hESC derived neural progenitor cells and also highlighted the need for systematic evaluations of hESC derived transplants to optimise their safety in vivo. These results are beneficial in demonstrating the realistic therapeutic potential held by these two cell sources. They demonstrate how transient interventions can enhance therapeutic outcomes of neural progenitor cell transplantation for HD and have developed the understanding of neural progenitor cell transplantation as a therapeutic tool, bringing transplantation from different cell sources closer to eventual translation for HD sufferers.

Whole document restricted, see Access Instructions file below for details of how to access the print copy. / Huntington’s disease [HD] is a debilitating adult onset inherited neurodegenerative disorder with primary degeneration in the striatum and widespread secondary degeneration throughout the brain. There are currently no clinical treatments to prevent onset, delay progression or replace lost neurons. Striatal cell transplantation strategies under clinical evaluation appear viable and effective for the treatment of HD. However, the future of regenerative medicine lies in developing renewable, expandable multipotent neural cell sources for transplantation. This Thesis has investigated a range of novel developments for enhancing the therapeutic potential of neural progenitor cell transplantation in a quinolinic acid [QA] lesion rat model of HD using two cell sources, adult neural progenitor cells and human embryonic stem cell [hESC] derived neural progenitor cells. Chapter Three identified a novel method for in vitro lithium priming of adult neural progenitor cells which enhances their neurogenic potential at the expense of glial formation. Chapter Four demonstrated that lithium priming of adult neural progenitor cells altered their phenotypic fate in vivo after transplantation, enhancing regional specific differentiation and efferent projection formation. The therapeutic potential of this strategy was demonstrated by accelerated acquisition of motor function benefits in the QA model. Chapter Five then demonstrated the ability for post transplantation environmental enrichment to modify therapeutic functional outcomes in the QA lesion model, and through lithium priming and enrichment demonstrated that adult neural progenitors are amenable to combinatorial interventions which can alter their phenotypic fate and enhance anatomical integration. Chapter Six investigated the in vivo effects of in vitro noggin priming of hESC derived neural progenitor cells and identified enhanced safety and neuronal differentiation in the QA lesioned striatum after noggin priming. Furthermore Chapter Seven provided evidence for functional reconstruction and therapeutic functional benefits from transplantation of noggin primed hESC derived neural progenitor cells and also highlighted the need for systematic evaluations of hESC derived transplants to optimise their safety in vivo. These results are beneficial in demonstrating the realistic therapeutic potential held by these two cell sources. They demonstrate how transient interventions can enhance therapeutic outcomes of neural progenitor cell transplantation for HD and have developed the understanding of neural progenitor cell transplantation as a therapeutic tool, bringing transplantation from different cell sources closer to eventual translation for HD sufferers.

MicroRNA (miRNA) function is required for normal animal development, in particular in stem cell and precursor populations. I hypothesize that miRNAs are similarly required for stem cell maintenance and appropriate fate commitment in the brain. To test the requirement for global microRNA production, I depleted the microRNA biosynthetic enzyme DICER in the developing mouse brain. I found that DICER loss in embryonic neural progenitor cells leads to embryonic lethality with microcephaly. By histological analysis, I found defects in both neural progenitor cell maintenance and cell differentiation. I also identified new candidate microRNAs for this phenotype by profiling miRNAs in DICER-depleted and control cells. Three microRNAs which are good candidates to modulate nervous differentiation are miR-23b, -182, and -34a. I describe the expression pattern and functional characterization of these candidates. In particular, miR-34a depletes neuron production after progenitor cell differentiation in culture, likely by modulating cell cycling and Notch pathway genes.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第22639号 / 医博第4622号 / 新制||医||1044(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 林 康紀, 教授 伊佐 正, 教授 斎藤 通紀 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Alzheimer's disease (AD) leads to neurodegeneration resulting in cognitive and physical impairments. AD is denoted by accumulation of intracellular neurofibrillary tangles, known as tau, and extracellular plaques of the amyloid beta protein (Aβ). Aβ results from the proteolytic cleavage of the amyloid precursor protein (APP) by β- and gamma-secretases in the amyloidogenic pathway. Although, Aβ has been widely studied for neurodegeneration, the role of APP in both, the healthy and diseased conditions, has not yet been entirely understood. The function that APP has in neural stem cell (NSC) proliferation, differentiation, and migration during adult neurogenesis has been previously studied. Additionally, APP has be shown to be overexpressed after neural damage resulted from conditions, such as AD and traumatic brain injury (TBI). In this study, the role of APP in in vitro damaged neural tissue cells was further investigated by evaluating neural progenitor cell proliferation, migration, and differentiation after a scratch assay. For these purposes, induced pluripotent stem (iPS) cells from AD patients were differentiated into neural progenitor cells to model the disease conditions and later treated with Phenserine to reduce their levels of APP expression. The results suggested that APP may enhance neural progenitor cell proliferation and glial differentiation while inhibiting neural progenitor cell migration and neuronal cell specialization after neural tissue damage.

Adult hippocampal neurogenesis, or the process of creating new neurons in the dentate gyrus (DG) of the hippocampus, underlies learning and memory capacity. This cognitive ability is essential for humans to operate in their everyday lives, but cognitive disruption can occur in response to traumatic insult such as brain injury. Previous findings in rodent models have characterized the effect of moderate traumatic brain injury (TBI) on neurogenesis and found learning and memory shortfalls correlated with limited neurogenic capacity. While there are no substantial changes after one mild TBI, research has yet to determine if neurogenesis contributes to the worsened cognitive outcomes of repetitive mild TBI. Here, we examined the effect of neurogenesis on cognitive decline following repetitive mild TBI by utilizing AraC to limit the neurogenic capacity of the DG. Utilizing a BrdU fate-labeling strategy, we found a significant increase in the number of immature neurons that correlate learning and memory impairment. These changes were attenuated in AraC-treated animals. We further identified endothelial cell (EC)-specific EphA4 receptor as a key mediator of aberrant neurogenesis. Taken together, we conclude that increased aberrant neurogenesis contributes to learning and memory deficits after repetitive mild TBI. / Doctor of Philosophy / In the United States, millions of people experience mild traumatic brain injuries, or concussions, every year. Patients often have a lower ability to learn and recall new information, and those who go on to receive more concussions are at an increased risk of developing long-term memory-associated disorders such as dementia and chronic traumatic encephalopathy. Despite the high number of athletes and military personnel at risk for these disorders, the underlying cause of long-term learning and memory shortfalls associated with multiple concussions remains ill defined. In the brain, the hippocampus play an important role in learning and memory and is one of only two regions in the brain where new neurons are created from neural stem cells through the process of neurogenesis. Our study seeks to address the role of neurogenesis in learning and memory deficits in mice. These findings provide the foundation for future, long-term mechanistic experiments that uncover the aberrant or uncontrolled processes that derail neurogenesis after multiple concussions. In short, we found an increase in the number of newborn immature neurons that we classify as aberrant neurogenesis. Suppressing this process rescued the learning and memory problems in a rodent model of repeated concussion. These findings improve our understanding of the processes that contribute to the pathophysiology of TBI.

Williams Beuren syndrome Syndrome (WBS) and 7q11.23 Duplication Syndrome (Dup7) are rare neurodevelopmental disorders associated with a range of cognitive and behavioural symptoms, caused by the deletion and duplication, respectively, of 26 genes on human chromosome 7q11.23. I have studied the effects of deletion or duplication of two candidate genes, GTF2I and GTF2IRD1, on neural stem cell growth and neurogenesis using cultured primary neuronal precursors from mouse models with gene copy number changes. I found that the number of neuronal precursors and committed neurons was directly related to the copy number of these genes in the mid-gestation embryonic cortex. I further found that in late-gestation embryos, cortical thickness was altered in a similar gene dose-dependent manner, in combination with layer-specific changes in neuronal density. I hypothesize that some of the neurological features of WS and Dup7 stem from these impairments in early cortical development.

Williams Beuren syndrome Syndrome (WBS) and 7q11.23 Duplication Syndrome (Dup7) are rare neurodevelopmental disorders associated with a range of cognitive and behavioural symptoms, caused by the deletion and duplication, respectively, of 26 genes on human chromosome 7q11.23. I have studied the effects of deletion or duplication of two candidate genes, GTF2I and GTF2IRD1, on neural stem cell growth and neurogenesis using cultured primary neuronal precursors from mouse models with gene copy number changes. I found that the number of neuronal precursors and committed neurons was directly related to the copy number of these genes in the mid-gestation embryonic cortex. I further found that in late-gestation embryos, cortical thickness was altered in a similar gene dose-dependent manner, in combination with layer-specific changes in neuronal density. I hypothesize that some of the neurological features of WS and Dup7 stem from these impairments in early cortical development.