No description available.

No description available.

Progressive degeneration in the central nervous system (CNS) of Huntington’s disease (HD) patients is a relentless debilitating process, resulting from the inheritance of a single gene mutation. With limited knowledge of the underlying pathological molecular mechanisms, pharmaceutical intervention has to-date not provided any effective clinical treatment strategies to attenuate or compensate the neuronal cell death. Attention has therefore turned to biotherapeutic molecules and novel treatment approaches to promote restoration and protection of selectively vulnerable populations of neurons in the HD brain. Rapid advances in vectorology and gene-based medicine over the past decade have opened the way for safe and efficient delivery of biotherapeutics to the CNS. With numerous factors known to regulate the development, plasticity and maintenance of the mammalian nervous system many proteins have emerged as potential therapeutic agents to alleviate HD progression. This investigative study utilised gene delivery vectors derived from the non-pathogenic adeno-associated virus (AAV) to direct high-level expression of brain-derived neurotrophic factor (BDNF), glial cell-line derived neurotrophic factor (GDNF), Bcl-xL or X-linked inhibitor of apoptosis protein (XIAP) within the rodent striatum. Maintenance of the basal ganglia and functional behaviour deficits were assessed following excitotoxic insult of the striatum by quinolinic acid (QA), a neurotoxic model of HD pathology. Enhanced striatal expression of BDNF prior to QA-induced lesioning provided maintenance of the striosome-matrix organisation of the striatum, attenuating impairments of sensorimotor behaviour with a 36-38% increase in the maintenance of DARPP-32 / krox-24 expressing striatal neurons, reduced striatal atrophy and increased maintenance of striatonigral projections. Higher levels of BDNF however induced seizures and weight-loss highlighting the need to provide regulatable control over biotherapeutic protein expression. Continuous high-expression of BDNF or GDNF resulted in a downregulation of intracellular signal mediating proteins including DARPP-32, with AAV-GDNF not found to enhance the overall maintenance of striatal neurons. Neither of the anti-apoptotic factors provided significant protection of transduced striatal neurons but tended towards ameliorating QA-induced behavioural deficits, displaying behaviour – pathology correlations with the survival of parvalbumin-expressing neurons in the globus pallidus. The results of this thesis suggest BDNF as a promising putative biotherapeutic for HD, but emphasises the requirement to control expression following gene delivery, and for further elucidation of the physiological impact that enhanced expression of endogenous factors has on the host cells. Additionally the maintenance of neural networks beyond the caudate-putamen will be vital to ensuring efficient clinical outcomes for HD. / Auckland Medical Research Foundation. Foundation for Research, Science and Technology. The University of Auckland.

No description available.

No description available.

Photoreceptors are of prime importance for humans, since vision is one of the most important senses for us. In our daily life, where nearly every action is dependent on visual input, an impairment or a loss of eyesight leads to severe disability. With a non-syndromic prevalence of 1:4000, retinitis pigmentosa, a collective term for a group of inherited retinal eye diseases, represents, together with age-related macula degeneration, one of the main causes for visual impairment and blindness in industrialized countries. The dominant reason for vision loss is, in both cases, the irreversible loss of photoreceptor cells located in the outer nuclear layer of the retina. To date, no effective treatment is available to preserve or regain visual function in affected patients. Recent promising strategies for new retinal therapeutical approaches focus on one hand on the development of gene therapies, where an introduced wild-type allele compensates a mutated gene, and on the other hand on cell therapies, where stem or photoreceptor precursor cells (PPCs) are transplanted to the sub-retinal space to replace degenerated host photoreceptors. The current study is subdivided into three parts, addressing the issue of non-reversible photoreceptor cell loss due to retinal degenerative diseases by investigating in the first two parts new qualitative as well as quantitative approaches in the field of retinal cell therapy, while in the third part an ocular gene therapeutical approach targeting prominin-1, a gene involved in retinal degenerative disorders, was investigated. Briefly, this study shows in the first part, a significant enhancement of the integration rate of PPCs in wild-type host retinas, achieved by pre-transplantational sorting, using the recently discovered PPC - specific cell surface marker CD73. This sets another step further towards retinal cell therapy by increasing the effectiveness of such treatment. Next to this quantitative approach, it is also shown that the quality of transplanted photoreceptor precursor cells is comparable to native photoreceptors by demonstrating, that an indispensable prerequisite of every photoreceptor cell, the outer segment, is developed by transplanted PPCs after proper integration. Importantly, transplanted PPCs develop native outer segments even when not integrated in the host tissue but located in the sub-retinal space, as it is predominantly observed after transplantation into severely degenerated retinas. These results substantiate the feasibility of cell therapeutical treatment of severely degenerated retinas. At the end of this part, it is demonstrated, that outer segments are not formed properly by PPCs transplanted to the vitreal side of the retina. This suggests an influence of signaling molecules, presumably secreted by retinal pigment epithelial cells into the sub-retinal space, on transplanted PPC final differentiation. Since intensive research is done to differentiate stem cells into PPCs for cell therapeutical transplantation, these results may contribute significantly to this research by demonstrating, that factors secreted by the retinal pigment epithelium might play a crucial role for successful stem cell to PPC differentiation. The last part of my work investigates a gene therapeutical approach to cure inherited retinal degenerative diseases. One gene, where reported mutations cause retinal degeneration in humans is prominin-1, a protein expressed at cell membrane evaginations in a variety of cell types. Interestingly, the prominin-1 knock-out mouse is characterized exclusively by disorganized photoreceptor outer segment formation and progressive retinal degeneration. Successful delivery of a wild-type form of mouse prominin-1 using adeno-associated viral vector transfer, into the photoreceptors of prominin-1 - deficient mice is demonstrated. The divergent results show on one hand a rescue of the thickness of the photoreceptor outer nuclear layer on a short time period (3 weeks post treatment), and on the other hand long-term data (8-10 weeks post treatment) suggests histologically as well as functionally a negative effect on treated photoreceptors. This might be due to effects caused by an over-expression of prominin-1 and will be investigated in future studies. In conclusion, distinct and important investigations were made which contribute significant puzzle pieces to new cell- as well as gene therapeutical approaches for the treatment of retinal degenerative disorders.

Progressive degeneration in the central nervous system (CNS) of Huntington’s disease (HD) patients is a relentless debilitating process, resulting from the inheritance of a single gene mutation. With limited knowledge of the underlying pathological molecular mechanisms, pharmaceutical intervention has to-date not provided any effective clinical treatment strategies to attenuate or compensate the neuronal cell death. Attention has therefore turned to biotherapeutic molecules and novel treatment approaches to promote restoration and protection of selectively vulnerable populations of neurons in the HD brain. Rapid advances in vectorology and gene-based medicine over the past decade have opened the way for safe and efficient delivery of biotherapeutics to the CNS. With numerous factors known to regulate the development, plasticity and maintenance of the mammalian nervous system many proteins have emerged as potential therapeutic agents to alleviate HD progression. This investigative study utilised gene delivery vectors derived from the non-pathogenic adeno-associated virus (AAV) to direct high-level expression of brain-derived neurotrophic factor (BDNF), glial cell-line derived neurotrophic factor (GDNF), Bcl-xL or X-linked inhibitor of apoptosis protein (XIAP) within the rodent striatum. Maintenance of the basal ganglia and functional behaviour deficits were assessed following excitotoxic insult of the striatum by quinolinic acid (QA), a neurotoxic model of HD pathology. Enhanced striatal expression of BDNF prior to QA-induced lesioning provided maintenance of the striosome-matrix organisation of the striatum, attenuating impairments of sensorimotor behaviour with a 36-38% increase in the maintenance of DARPP-32 / krox-24 expressing striatal neurons, reduced striatal atrophy and increased maintenance of striatonigral projections. Higher levels of BDNF however induced seizures and weight-loss highlighting the need to provide regulatable control over biotherapeutic protein expression. Continuous high-expression of BDNF or GDNF resulted in a downregulation of intracellular signal mediating proteins including DARPP-32, with AAV-GDNF not found to enhance the overall maintenance of striatal neurons. Neither of the anti-apoptotic factors provided significant protection of transduced striatal neurons but tended towards ameliorating QA-induced behavioural deficits, displaying behaviour – pathology correlations with the survival of parvalbumin-expressing neurons in the globus pallidus. The results of this thesis suggest BDNF as a promising putative biotherapeutic for HD, but emphasises the requirement to control expression following gene delivery, and for further elucidation of the physiological impact that enhanced expression of endogenous factors has on the host cells. Additionally the maintenance of neural networks beyond the caudate-putamen will be vital to ensuring efficient clinical outcomes for HD. / Auckland Medical Research Foundation. Foundation for Research, Science and Technology. The University of Auckland.

Progressive degeneration in the central nervous system (CNS) of Huntington’s disease (HD) patients is a relentless debilitating process, resulting from the inheritance of a single gene mutation. With limited knowledge of the underlying pathological molecular mechanisms, pharmaceutical intervention has to-date not provided any effective clinical treatment strategies to attenuate or compensate the neuronal cell death. Attention has therefore turned to biotherapeutic molecules and novel treatment approaches to promote restoration and protection of selectively vulnerable populations of neurons in the HD brain. Rapid advances in vectorology and gene-based medicine over the past decade have opened the way for safe and efficient delivery of biotherapeutics to the CNS. With numerous factors known to regulate the development, plasticity and maintenance of the mammalian nervous system many proteins have emerged as potential therapeutic agents to alleviate HD progression. This investigative study utilised gene delivery vectors derived from the non-pathogenic adeno-associated virus (AAV) to direct high-level expression of brain-derived neurotrophic factor (BDNF), glial cell-line derived neurotrophic factor (GDNF), Bcl-xL or X-linked inhibitor of apoptosis protein (XIAP) within the rodent striatum. Maintenance of the basal ganglia and functional behaviour deficits were assessed following excitotoxic insult of the striatum by quinolinic acid (QA), a neurotoxic model of HD pathology. Enhanced striatal expression of BDNF prior to QA-induced lesioning provided maintenance of the striosome-matrix organisation of the striatum, attenuating impairments of sensorimotor behaviour with a 36-38% increase in the maintenance of DARPP-32 / krox-24 expressing striatal neurons, reduced striatal atrophy and increased maintenance of striatonigral projections. Higher levels of BDNF however induced seizures and weight-loss highlighting the need to provide regulatable control over biotherapeutic protein expression. Continuous high-expression of BDNF or GDNF resulted in a downregulation of intracellular signal mediating proteins including DARPP-32, with AAV-GDNF not found to enhance the overall maintenance of striatal neurons. Neither of the anti-apoptotic factors provided significant protection of transduced striatal neurons but tended towards ameliorating QA-induced behavioural deficits, displaying behaviour – pathology correlations with the survival of parvalbumin-expressing neurons in the globus pallidus. The results of this thesis suggest BDNF as a promising putative biotherapeutic for HD, but emphasises the requirement to control expression following gene delivery, and for further elucidation of the physiological impact that enhanced expression of endogenous factors has on the host cells. Additionally the maintenance of neural networks beyond the caudate-putamen will be vital to ensuring efficient clinical outcomes for HD. / Auckland Medical Research Foundation. Foundation for Research, Science and Technology. The University of Auckland.

Progressive degeneration in the central nervous system (CNS) of Huntington’s disease (HD) patients is a relentless debilitating process, resulting from the inheritance of a single gene mutation. With limited knowledge of the underlying pathological molecular mechanisms, pharmaceutical intervention has to-date not provided any effective clinical treatment strategies to attenuate or compensate the neuronal cell death. Attention has therefore turned to biotherapeutic molecules and novel treatment approaches to promote restoration and protection of selectively vulnerable populations of neurons in the HD brain. Rapid advances in vectorology and gene-based medicine over the past decade have opened the way for safe and efficient delivery of biotherapeutics to the CNS. With numerous factors known to regulate the development, plasticity and maintenance of the mammalian nervous system many proteins have emerged as potential therapeutic agents to alleviate HD progression. This investigative study utilised gene delivery vectors derived from the non-pathogenic adeno-associated virus (AAV) to direct high-level expression of brain-derived neurotrophic factor (BDNF), glial cell-line derived neurotrophic factor (GDNF), Bcl-xL or X-linked inhibitor of apoptosis protein (XIAP) within the rodent striatum. Maintenance of the basal ganglia and functional behaviour deficits were assessed following excitotoxic insult of the striatum by quinolinic acid (QA), a neurotoxic model of HD pathology. Enhanced striatal expression of BDNF prior to QA-induced lesioning provided maintenance of the striosome-matrix organisation of the striatum, attenuating impairments of sensorimotor behaviour with a 36-38% increase in the maintenance of DARPP-32 / krox-24 expressing striatal neurons, reduced striatal atrophy and increased maintenance of striatonigral projections. Higher levels of BDNF however induced seizures and weight-loss highlighting the need to provide regulatable control over biotherapeutic protein expression. Continuous high-expression of BDNF or GDNF resulted in a downregulation of intracellular signal mediating proteins including DARPP-32, with AAV-GDNF not found to enhance the overall maintenance of striatal neurons. Neither of the anti-apoptotic factors provided significant protection of transduced striatal neurons but tended towards ameliorating QA-induced behavioural deficits, displaying behaviour – pathology correlations with the survival of parvalbumin-expressing neurons in the globus pallidus. The results of this thesis suggest BDNF as a promising putative biotherapeutic for HD, but emphasises the requirement to control expression following gene delivery, and for further elucidation of the physiological impact that enhanced expression of endogenous factors has on the host cells. Additionally the maintenance of neural networks beyond the caudate-putamen will be vital to ensuring efficient clinical outcomes for HD. / Auckland Medical Research Foundation. Foundation for Research, Science and Technology. The University of Auckland.

Progressive degeneration in the central nervous system (CNS) of Huntington’s disease (HD) patients is a relentless debilitating process, resulting from the inheritance of a single gene mutation. With limited knowledge of the underlying pathological molecular mechanisms, pharmaceutical intervention has to-date not provided any effective clinical treatment strategies to attenuate or compensate the neuronal cell death. Attention has therefore turned to biotherapeutic molecules and novel treatment approaches to promote restoration and protection of selectively vulnerable populations of neurons in the HD brain. Rapid advances in vectorology and gene-based medicine over the past decade have opened the way for safe and efficient delivery of biotherapeutics to the CNS. With numerous factors known to regulate the development, plasticity and maintenance of the mammalian nervous system many proteins have emerged as potential therapeutic agents to alleviate HD progression. This investigative study utilised gene delivery vectors derived from the non-pathogenic adeno-associated virus (AAV) to direct high-level expression of brain-derived neurotrophic factor (BDNF), glial cell-line derived neurotrophic factor (GDNF), Bcl-xL or X-linked inhibitor of apoptosis protein (XIAP) within the rodent striatum. Maintenance of the basal ganglia and functional behaviour deficits were assessed following excitotoxic insult of the striatum by quinolinic acid (QA), a neurotoxic model of HD pathology. Enhanced striatal expression of BDNF prior to QA-induced lesioning provided maintenance of the striosome-matrix organisation of the striatum, attenuating impairments of sensorimotor behaviour with a 36-38% increase in the maintenance of DARPP-32 / krox-24 expressing striatal neurons, reduced striatal atrophy and increased maintenance of striatonigral projections. Higher levels of BDNF however induced seizures and weight-loss highlighting the need to provide regulatable control over biotherapeutic protein expression. Continuous high-expression of BDNF or GDNF resulted in a downregulation of intracellular signal mediating proteins including DARPP-32, with AAV-GDNF not found to enhance the overall maintenance of striatal neurons. Neither of the anti-apoptotic factors provided significant protection of transduced striatal neurons but tended towards ameliorating QA-induced behavioural deficits, displaying behaviour – pathology correlations with the survival of parvalbumin-expressing neurons in the globus pallidus. The results of this thesis suggest BDNF as a promising putative biotherapeutic for HD, but emphasises the requirement to control expression following gene delivery, and for further elucidation of the physiological impact that enhanced expression of endogenous factors has on the host cells. Additionally the maintenance of neural networks beyond the caudate-putamen will be vital to ensuring efficient clinical outcomes for HD. / Auckland Medical Research Foundation. Foundation for Research, Science and Technology. The University of Auckland.