Biology subjects

Selwood, D. L.

Publications and source records attributed to Selwood, D. L..

4 recordsLinked to original sources

bioRxiv2025

A modified cyclosporine enhances lentivector transduction ex vivo and in vivo by degrading IFITM3

Intrinsic innate immune barriers have evolved to suppress viral infection and can reduce effective gene delivery in gene therapy. We have developed BG147, a novel cyclosporine A analogue, optimised via structure-guided design to prevent inhibition of HIV cofactor Cyclophilin A and to specifically inhibit interferon-induced transmembrane proteins (IFITM1-3). BG147 enhances VSV-G pseudotyped lentiviral vector transduction ex vivo in hematopoietic stem and progenitor cells (HSPCs) and in in vivo ocular gene therapy of photoreceptor cells in mice. Upon BG147 treatment, IFITM proteins are mislocalised and degraded through lysosomal acidification-dependent pathways. IFITM3 levels functionally return in cells 96 h after BG147 washout. BG147 promises to transform ex vivo and in vivo eye gene therapies by transiently inhibiting intrinsic immune barriers mediated by IFITM proteins to enhance a wide range of protocols. One Sentence SummaryModified cyclosporine, BG147, enhances lentivector gene therapy transduction, ex vivo in HSPC and in vivo in mouse photoreceptors, by degrading IFITM3.

cell biology↗

bioRxiv2025

Pathogenic variants in autophagy-tethering factor EPG5 drive neurodegeneration through mitochondrial dysfunction and innate immune activation

The autophagy-tethering factor, ectopic P-granule 5 autophagy protein (EPG5), plays a key role in autophagosome-lysosome fusion. Impaired autophagy associated with pathogenic variants in EPG5 cause a rare devastating multisystem disorder known as Vici syndrome, which includes neurodevelopmental defects, severe progressive neurodegeneration and immunodeficiency. The pathophysiological mechanisms driving disease presentation and progression are not understood. In patient-derived fibroblasts and iPS cells differentiated to cortical neurons, we found that impaired mitophagy leads to mitochondrial bioenergetic dysfunction. Physiological Ca2+ signals resulted in paradoxical mitochondrial Ca2+ overload attributed to downregulation of MICU1/3. Ca2+ signals caused mitochondrial depolarisation, mtDNA release and activation of the cGAS-STING pathway, reversed by pharmacological inhibition of the mitochondrial permeability transition pore (mPTP) or of the STING pathway. Thus, we have identified multiple potential therapeutic targets driving disease progression associated with pathogenic EPG5 mutations, including impaired mitochondrial bioenergetics, mitochondrial Ca2+ overload, vulnerability to mPTP opening and activation of innate immune signalling.

neuroscience↗

bioRxiv2024

Inhibition of GEF-H1-RhoA signaling in inflammation with a stapled peptide mimicry of the RhoA67-78 helix

Guanine exchange factors (GEFs) are considered hard to drug with conventional small molecules, they lack conventional deep binding pockets and binding ligands are seldom reported. Here we report the design of a stapled peptide stP5 targeting the interaction between cytoskeletal regulator RhoA GTPase and its activator guanine exchange factor H1 (GEF-H1). StP5 is a modified RhoA mimic based on a previously identified bioactive -helical epitope to GEF-H1. StP5 effectively inhibits GEF-H1-induced morphological and transcriptional changes in cellular models for inflammation and does not affect the related GEF p114RhoGEF (ARHGEF18). StP5 peptide is approximately 100 fold more active in cellular assays than the unstapled P5 peptide. We provide a bioinformatic analysis of the stP5 bindings site in different GEFs, providing a basis for this selectivity. The GEF-H1 inhibitor stP5 represents a step towards fully drugging GEF-H1. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=102 SRC="FIGDIR/small/624118v1_ufig1.gif" ALT="Figure 1"> View larger version (38K): org.highwire.dtl.DTLVardef@d783b3org.highwire.dtl.DTLVardef@10798b2org.highwire.dtl.DTLVardef@1ba0817org.highwire.dtl.DTLVardef@693367_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2024

Development of the ULK1-Recruiting Chimeras (ULKRECs) to enable proximity-induced and ULK1-dependent degradation of mitochondria

Targeted protein degradation (TPD) has opened new opportunities to investigate signalling pathways as a research tool, and as a unique therapeutic strategy using bifunctional chimeric small molecules, with candidate molecules in clinical trials for the treatment of breast cancer and prostate cancer. Most current TPD approaches use the 26S proteasomal machinery via PROteolysis TArgeting Chimeras (PROTACs), however, new emerging strategies using the autophagy system, termed AUtophagy TArgeting Chimeras (AUTACs) expand on the degrader arsenal and repertoire of targets that can be degraded. This includes non-protein molecules such as lipid droplets, organelles, insoluble protein aggregates as well as typical TPD targets, soluble intracellular proteins. AUTACs were proposed to operate by binding the target of interest (TOI) and linking it to an autophagy cargo protein (LC3 or p62), tethering the TOI into forming autophagosomes. In this study, we designed an alternative strategy for AUTACs, reasoning that the local recruitment and activation of ULK1 is sufficient to induce the formation of an autophagosome at the site of recruitment. As a proof of concept, we used an ULK1 agonist linked to a mitochondrial targeting ligand and termed these chimeric molecules ULK1-Recruiting Chimeras (ULKRECs). We show that local activation of ULK1 by ULKRECs at the outer mitochondrial membrane (OMM) induces mitophagy, further enhanced by mitochondrial insult. Using Parkinsons disease (PD) patient-derived fibroblasts, we show the ULKRECs induce mitophagy independently of the PRKN/PINK axis, components required to signal for canonical mitophagy in response to stressors and often dysfunctional in many neurological diseases. We propose that ULKRECs are a novel class of degraders that have potential as unique therapeutics for diseases where dysfunctional mitophagy plays a key role in disease pathology and progression.

cell biology↗