Biology subjects

Luft, C.

Publications and source records attributed to Luft, C..

3 recordsLinked to original sources

bioRxiv2024

Functional analyses and integrated mechanisms of cellular destruction by L-amino acid oxidase

Snakebite accidents are prevalent worldwide and cause a spectrum of severe clinical manifestations and reduction of patient quality of life and economic income. L-amino acid oxidase (LAAO) is a highly toxic enzyme present in various venoms that causes tissue necrosis, oedema, coagulopathies, and organ failure. Here we investigate the mechanisms of LAAO cytotoxicity preceding cell death using recombinant LAAO and a catalytic inactive LAAO mutant. Wild-type LAAO uptake by cells leads to a decrease in lysosome number and size and inhibition of autophagy flux. Mitochondria function is impaired by severe proton leakage and mitochondrial fission is stimulated. Despite engulfment by autophagosomes, mitochondrial clearance is prevented by the lysosomal defects. The coordinate multi-organelle dysfunction strongly perturbs energy production, cell metabolism and clearance of defective organelles by autophagy, thereby triggering an irreversible destructive path. Considering the fast organelle impairment, strategies to reduce multi-organelle injury after LAAO exposure may be effective to maintain critical cell functions and strengthen adaptive responses against cytotoxicity.

cell biology↗

bioRxiv2023

Cardiac glycosides restore autophagy flux in an iPSC-derived neuronal model of WDR45 deficiency

Beta-Propeller Protein-Associated Neurodegeneration (BPAN) is one of the commonest forms of Neurodegeneration with Brain Iron Accumulation, caused by mutations in the gene encoding the autophagy-related protein, WDR45. The mechanisms linking autophagy, iron overload and neurodegeneration in BPAN are poorly understood and, as a result, there are currently no disease-modifying treatments for this progressive disorder. We have developed a patient-derived, induced pluripotent stem cell (iPSC)-based midbrain dopaminergic neuronal cell model of BPAN (3 patient, 2 age-matched controls and 2 isogenic control lines) which shows defective autophagy and aberrant gene expression in key neurodegenerative, neurodevelopmental and collagen pathways. A high content imaging-based medium-throughput blinded drug screen using the FDA-approved Prestwick library identified 5 cardiac glycosides that both corrected disease-related defective autophagosome formation and restored BPAN-specific gene expression profiles. Our findings have clear translational potential and emphasise the utility of iPSC-based modelling in elucidating disease pathophysiology and identifying targeted therapeutics for early-onset monogenic disorders.

cell biology↗

bioRxiv2021

Investigation of USP30 inhibition to enhance Parkin-mediated mitophagy: tools and approaches

Mitochondrial dysfunction is implicated in Parkinson disease (PD). Mutations in Parkin, an E3 ubiquitin ligase, can cause juvenile-onset Parkinsonism probably through impairment of mitophagy. Inhibition of the de-ubiquitinating enzyme USP30 may counter this effect to enhance mitophagy. Using different tools and cellular approaches, we wanted to independently confirm this claimed role for USP30. Pharmacological characterization of additional tool compounds that selectively inhibit USP30 are reported. The consequence of USP30 inhibition by these compounds, siRNA knockdown and overexpression of dominant-negative USP30 in the mitophagy pathway in different disease-relevant cellular models was explored. Knockdown and inhibition of USP30 showed increased p-Ser65-ubiquitin levels and mitophagy in neuronal cell models. Furthermore, patient-derived fibroblasts carrying pathogenic mutations in Parkin showed reduced p-Ser65-ubiquitin levels compared to wild-type cells, levels that could be restored using either USP30 inhibitor or dominant-negative USP30 expression. Our data provide additional support for USP30 inhibition as a regulator of the mitophagy pathway.

neuroscience↗