Biology subjects

Mccarthy, A.

Publications and source records attributed to Mccarthy, A..

3 recordsLinked to original sources

bioRxiv2026

Microfluidic analysis reveals ROCK2 regulation of endothelial cilia is essential for blood vessel lumen formation and vascular integrity

BackgroundThe formation of a patent vascular lumen is fundamental to circulatory function, a process governed by cytoskeletal dynamics and mechanosensory signalling. Endothelial cilia are present during blood vessel lumen development, but their precise functional role remains poorly understood. Understanding how cilia coordinate with endothelial cytoskeletal and signalling pathways is critical for elucidating mechanisms of vascular morphogenesis. MethodsWe have established a microfluidic system that recapitulates endothelial tube formation under fluid flow, enabling pharmacological and genetic manipulation with real-time visualisation of tube behaviour. Cilia, cytoskeletal dynamics, and lumen development were analysed in vitro, and in vivo. ResultsEarly perfusion in the microfluidic system induced a hierarchical vascular network. Inhibiting Rho-kinase (ROCK) or knocking down ciliary components (IFT88 and RPGRIPL1) suppressed lumen formation. ROCK inhibition or genetic ablation disrupted cilia in endothelial and non-endothelial cells, associated with LIM-kinase inhibition. Crucially, ROCK2 genetic ablation caused endothelial cilia loss, misorientation, and abrogated lumen formation, leading to haemorrhages and compromised vascular integrity in vivo. ConclusionsOur findings unveil a previously unrecognised co-regulation between cilia and ROCK signalling essential in vascular lumen formation.

cell biology↗

bioRxiv2024

Live imaging human embryos reveals mitotic errors and lineage specification prior to implantation

Meiotic and mitotic chromosome segregation errors in human development have been studied mostly prior to and at the time of fertilisation. Despite chromosomal errors being a leading cause of miscarriage and infertility, chromosome missegregation has not been extensively studied at later stages of human development. Here we optimised labelling, light-sheet live imaging and semi-quantitative analysis of human embryos and reveal chromosome segregation errors just prior to implantation. We found that human embryos exhibited a number of chromosome missegregation events including multipolar spindle formation, lagging chromosomes, misalignment and chromosome slippage. We found that the majority of lagging chromosomes were passively inherited by one of the daughter cells, instead of reincorporating into the nuclei, suggesting a distinct pattern of micronuclei inheritance. By semi-automated segmentation, we tracked the position of labelled cells in human embryos and observed that while most labelled cells remained segregated to the outside, and therefore restricted to a placental-progenitor fate, there was evidence of a rare cell migration to cells positioned on the inside, which suggests that there may be plasticity. Altogether, we found that mitotic chromosome segregation errors arise just prior to implantation, which has implications for our understanding of biological events that contribute to aneuploidy mosaicism.

developmental biology↗

bioRxiv2020

BAcTrace a new tool for retrograde tracing of neuronal circuits

New tools and techniques have enabled many key advances in our understanding of the brain. To elucidate circuit function, it is necessary to identify, record from and manipulate networks of connected neurons. Here we present BAcTrace (Botulinum Activated Tracer), the first fully genetically encoded, retrograde, transsynaptic labelling system. BAcTrace is based on C. botulinum neurotoxin A, Botox, which we have engineered to act as a Trojan horse that jumps retrogradely between neurons to activate an otherwise silent transcription factor. We validate BAcTrace at three connections in the Drosophila olfactory system and show that it enables electrophysiological recordings of connected neurons. Finally, in a challenging circuit with highly divergent connections, we used Electron Microscopy connectomics to show that BAcTrace correctly identifies 12 out of 16 connections.

neuroscience↗