I026 Screening for mitochondrial therapeutics in Huntington’s disease using patient-derived cells

<h3>Background</h3> Mitochondrial dysfunction is widely reported in models of Huntington’s disease (HD), including altered respiratory complex activity, altered mitochondrial membrane potential and changes in mitophagy. However, whether mitochondrial function could be rescued as a therapeutic target in HD is under explored. This study sought to determine whether HD donor-derived fibroblasts could be used to identify modulators of mitochondrial function with therapeutic potential. <h3>Methods</h3> Fibroblasts from 3 HD donors and 3 age-matched control donors were characterised for respiration, and total cellular ATP levels. High content imaging was used to assess multiple parameters of mitochondrial function, mitochondrial morphology and mitophagy flux. Tool compounds predicted to affect mitochondrial function were selected for screening using high throughput imaging. <h3>Results</h3> Mitochondria from HD donor-derived fibroblasts display similar ATP levels and basal respiration to controls but significantly lower maximal respiration under uncoupling conditions. High content imaging identified alterations in mitochondrial morphology that were consistent across all HD cell lines and alterations in number and mitochondrial membrane potential that are specific to individual patient cell lines. HD donor-derived fibroblasts displayed altered mitophagy flux under mitophagy inducing conditions. Proof-of-principle live imaging screening identified A769662 which can enhance the proportion of functional mitochondria in HD donor-derived fibroblasts. <h3>Conclusions</h3> This study has identified alterations in HD donor-derived fibroblasts in mitochondrial morphology, function, and clearance, indicating multiple potential target areas for screening for therapeutic intervention. Proof-of-principle screening identified a modulator of mitochondrial function, confirming the potential of using HD donor-derived fibroblasts with high content imaging to identify mitochondrial therapeutics for HD.