Biology subjects

Bennington, A.

Publications and source records attributed to Bennington, A..

3 recordsLinked to original sources

bioRxiv2026

Prpf8N1531S homozygous mutant mouse embryos have multiple defects in cardiac development and show aberrant splicing of the cardiac transcription factor Tead1

Mutations in the spliceosomal gene PRPF8 are associated with a range of human diseases. Studies in mouse and zebrafish suggest that Prpf8 also has a developmental function. Here, using a Prpf8 mutant mouse line isolated from a chemical induced mutagenesis screen, we uncover a previously unrecognised and essential role for Prpf8 in heart development, consistent with the embryonic lethality observed in Prpf8N1531S homozygous mutants. Prpf8N1531S mutant embryos display severe defects in ventricular trabeculation and compact zone formation, accompanied by increased cardiomyocyte proliferation specifically in the compact zone. Mutant embryonic hearts also exhibit disrupted cellular organisation, altered cytoskeletal architecture and changes in extracellular matrix protein expression. Notably, these cardiac abnormalities were exacerbated in embryos exhibiting cardiac looping defects. Transcriptomic analysis identified multiple aberrantly spliced transcripts in Prpf8N1531S mutant embryos, among which the cardiac transcription factor Tead1 was selected as a key functional candidate due to it known role in cardiac ventricle wall developemnt. Tead1 mis-splicing generated an in-frame, lower molecular weight protein isoform, associated with reduced overall TEAD1 expression. The Tead1 mis-spliced isoform showed altered nuclear localisation and dysregulation of TEAD1-dependent gene network important for heart development, including known cardiac sarcomeric genes. In addition, we observed reduced levels of the intracellular domain of the NOTCH1 receptor (NICD1), indicating impaired Notch signalling.. These findings suggest that impaired TEAD1-dependent transcription and Notch signalling contribute to abnormal cardiac trabeculation and compact zone development, highlighting a critical role for Prpf8 in maintaining proper heart development through the regulation of cardiac transcription factor expression and associated signalling networks. This study offers new mechanistic insights into congenital heart diseases linked to spliceosomal gene mutations.

developmental biology↗

bioRxiv2026

Vascular dilation modulates brain haematoma expansion in larval zebrafish

Intracerebral haemorrhage (ICH) is a severe form of stroke with high morbidity and mortality rates. For survivors, acute haematoma expansion strongly determines neurological outcome. Although blood pressure reduction is widely investigated as a strategy to limit haematoma growth, the haemodynamic mechanisms regulating haemorrhage development remain poorly understood. Zebrafish provide a tractable in vivo model to study cerebrovascular biology and spontaneous ICH, yet the contribution of vascular regulation to haemorrhage onset and expansion has not been explored in this species. Here, we investigated whether pharmacological modulation of vascular dilation influences ICH development in zebrafish larvae. We first characterised vascular changes during the developmental window in which spontaneous ICH occurs and observed increased heart rate and progressive reductions in arterial diameter between 2 and 3 days post-fertilisation, suggesting increased vascular resistance. We then tested whether vasoconstriction promotes haemorrhage using angiotensin II, which induced systemic and cerebrovascular vasoconstriction but did not increase ICH incidence or haematoma size in two independent ICH models. In contrast, pharmacological vasodilation using sodium nitroprusside or isoproterenol significantly reduced haematoma size in a high-incidence model of atorvastatin-induced ICH. Live imaging of cerebral blood flow revealed that vasodilation was associated with the confinement of red blood cells around affected vessels rather than dispersing into the brain ventricles. Together, these findings indicate that vascular dilation modulates haemorrhage progression in zebrafish ICH and establish this model as a platform to investigate haemodynamic mechanisms regulating haematoma expansion.

cell biology↗

bioRxiv2024

25-hydroxycholesterol dysregulates brain endothelial cell function and exacerbates cerebral haemorrhage

The antiviral enzyme cholesterol 25-hydroxylase (CH25H) and its metabolite 25-hydroxycholesterol (25HC), which modulates cholesterol metabolism during infection, have been previously associated with vascular pathology. Viral infections have been linked to risk of intracerebral haemorrhage (ICH) but the molecular mechanisms leading to brain vessel rupture via antiviral responses remain unknown. We hypothesised that the CH25H/25HC pathway may impact neuroendothelial integrity in the context of infection-associated ICH. Here, using a SARS-CoV-2-spike-induced zebrafish ICH model and foetal human SARS-CoV-2-associated cortical tissue containing microbleeds, we identified an upregulation of CH25H in infection-associated cerebral haemorrhage. Using zebrafish ICH models and human brain endothelial cells, we asked whether 25HC may promote neurovascular dysfunction by modulating cholesterol metabolism. We found that 25HC and pharmacological inhibition of HMGCR by atorvastatin interacted to exacerbate brain bleeding in zebrafish larvae and in vitro brain endothelial dysfunction. In vitro 25HC-induced dysfunction was also rescued by cholesterol supplementation. These results demonstrate that the antiviral factor 25HC can dysregulate brain endothelial function by remodelling cholesterol metabolism. We propose that the CH25H/25HC pathway represents an important component in the pathophysiology of brain vessel dysfunction associated with infection and cholesterol dysregulation in the context of ICH. Summary StatementThe antiviral metabolite 25-hydroxycholesterol dysregulates brain endothelial function by remodelling cholesterol metabolism, thereby providing a mechanistic link between viral infection and brain endothelial dysfunction in conditions such as intracerebral haemorrhage.

neuroscience↗