Bhosale, G; (2018) Impact of mitochondrial calcium handling proteins on cell death in disease. Doctoral thesis (Ph.D), UCL (University College London).

Abstract

Aberrant cellular Ca2+ cycling has been implicated in many disease aetiologies. Mitochondria act as Ca2+ sinks, taking up Ca2+ which in turn regulates bioenergetics, mitochondrial function and maintenance. While mitochondrial Ca2+ buffering was first demonstrated 40 years ago, it was only in the last six years that the molecular identity of the main uptake mechanism and its regulators were discovered. Recently, two patient cohorts have been reported with loss-of-function mutations in MICU1, characterized by early onset neuronal and muscular defects (Logan et al 2014 & Lewis-Smith et al 2016). MICU1 is a regulator of the mitochondrial Ca2+ uniporter (MCU) and defines the threshold Ca2+ concentration at which the MCU opens. In order to further investigate the effect of the loss of this gate-keeping property on mitochondrial function, I carried out experiments performed with fibroblasts obtained from two patients with the c.1078-1G>C mutation from the Logan report and age-matched controls. As fibroblasts do not provide the ideal pathological context for this disease, a better model was sought. To this end, induced pluripotent stem cells were derived from the fibroblasts and then differentiated into neurons. To investigate the function of MICU1 in vivo, a knockout mouse model was characterised. While bioenergetics dysfunction can be a possible explanation for the disease phenotype, mitochondrial Ca2+ can also lead to cell death via the mitochondrial permeability transition pore when it surpasses a certain threshold. The mPTP has long been considered a druggable target for neurodegenerative disease. I investigated the properties of the pore in isolated mitochondria and cell lines using both Ca2+ and Δψm indicators using a multiwell plate format, with the aim of carrying out a drug screen for mPTP inhibitors. A pilot screen of compounds revealed potential candidates that can be used for further toxicity and efficacy screening. Ultimately, by combining the study of Ca2+ uptake with that of potential therapeutic tools to prevent Ca2+ induced cell death, this might contribute to future treatment options for a range of diseases.

Download activity - last month

Export as JSONCSVXML

Download activity - last 12 months

Export as JSONXMLCSV

Downloads by country - last 12 months

Export as XMLCSVJSON

Archive Staff Only

View Item