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Modulating the heat-shock response : a potential therapy for lysosomal storage disorders

Lysosomal storage disorders (LSDs) comprise a broad disease group of inherited metabolic disorders, the majority of which are associated with CNS pathology, significant disability and reductions in life expectancy. LSDs are caused by mutations in genes encoding proteins critical for the correct functioning of lysosomal homeostasis. The disruption of lysosomal homeostasis results in the abnormal accumulation of lysosomal content, initiating intracellular pathological events, including calcium dysregulation and lysosomal membrane permeablisation (LMP) affecting cell function and inducing cellular death mechanisms. These pathological events are particularly damaging within the CNS, due to its limited capacity for regeneration. Despite intensive scientific research into these disorders, and an increased understanding of the pathological events underlying these diseases, effective treatments are still lacking for most LSDs. Several therapeutic approaches have been investigated in the last 30 years, including enzyme replacement therapy, bone marrow transplantation, substrate reduction therapy, chemical chaperones and gene therapy. However, the CNS pathology in many of the LSDs remains unaddressed due to the restricted ability of many therapeutic agents to cross the blood-brain barrier. The heat-shock response (HSR) is an emerging element involved in the pathogenesis of a variety of disorders. The HSR is a physiological response to a wide range of cellular stresses. It functions to protect the cell from the aggregation of misfolded proteins and LMP. Of the HSR, several key players are integral to mounting a heat shock response, these include the heat-shock factor 1 (HSF-1) and HSP70. In this thesis, we provide proof-of-principle for the use of recombinant HSP70, and the small molecule up-regulator of the HSR, arimoclomol in treatment of a range of LSDs. We show that HSP70 is able to access the CNS, and increase the degradative capacity of lysosomal hydrolases. This provides differential behavioural, biochemical and survival effects in LSD models of Niemann-Pick type C, Sandhoff and Fabry disease. Additional studies using the HSF-1 upregulator arimoclomol, show a complex dose-response between the different models, possibly reflecting essential differences in the calcium dysregulation between these disease states.

Identiferoai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:711726
Date January 2014
CreatorsGray, James Andrew Russell
ContributorsPlatt, Frances
PublisherUniversity of Oxford
Source SetsEthos UK
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Sourcehttps://ora.ox.ac.uk/objects/uuid:d9b746c9-9026-4a6e-97b5-00bb848100d7

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