Biology subjects

Hewitt, B. J.

Publications and source records attributed to Hewitt, B. J..

3 recordsLinked to original sources

bioRxiv2026

Cross-omics profiling reveals cortical neuronal dysfunction following neonatal intraventricular haemorrhage that is attenuated by decorin treatment

Neonatal intraventricular haemorrhage (IVH) is a form of haemorrhagic stroke which is most common in premature infants and can cause mortality and lifelong disability. The reaction of brain tissue to extraneous blood is known to trigger several complications including post-haemorrhagic hydrocephalus (PHH), furthering the likelihood of neurological disability and death. The molecular response of the neuron-rich cortex to blood within the first 24 hours of injury, and how this may precipitate secondary brain injury or neurodegeneration, remains poorly defined. This lack of understanding may reduce the development of novel therapeutics aiming to limit the injury caused by neonatal IVH. Here, we utilised a proteome and transcriptome cross-omics approach to characterise cortical responses to blood in a neonatal mouse model of IVH to improve understanding of the effects and drivers of IVH-induced brain injury. The pleiotropic proteoglycan decorin, a well-characterised modulator of the inflammatory cytokine transforming growth factor beta 1, was also studied to identify if it can have any beneficial effects in the cortex. Cross-omics analysis between the transcriptome and proteome highlighted ferroptosis-associated signatures as a key post-IVH cortical injury mechanism. IVH caused a marked depletion of cortical neurons, neurofilaments, and synaptic vesicle proteins, observed through transcriptomics, immunostaining, and proteomics, which were attenuated by decorin treatment. Decorin also produced an enhanced phagocytic response potentially through activation of microglia. These findings highlight the vulnerability of cortical neurons to early injury following IVH in neonates and support decorin as a potential neuroprotective agent. They also suggest that ferroptosis-associated pathways may contribute to early cortical injury and represent a potential therapeutic target in this context.

neuroscience↗

bioRxiv2025

NRF2 upregulation by CDDO-Me protects AC16 human cardiomyocytes against doxorubicin-induced toxicity.

Doxorubicin (DOX) is an effective anticancer therapeutic but exhibits dose-dependent, potentially life-threatening cardiotoxicity. The specific mechanisms driving this cardiotoxicity are not fully understood but can include the induction of oxidative stress and subsequent cell death mechanism activation. This has prompted the exploration of NRF2, a master co-ordinator of antioxidant and largely cytoprotective pathways, as a potential approach for the alleviation of DOX-induced cardiotoxicity. Here, NRF2 was pharmacologically activated via CDDO-Me (hitherto referred to as CDDO) to reduce the negative consequences on AC16 human cardiomyocyte cell health and functions. NRF2 intracellular dynamics were quantitatively measured using live-cell imaging, demonstrating rapid ([~]10 min) yet sustained ([≥]24 h) induction of NRF2 expression and functional downstream activity. Genetic perturbations of the NRF2-KEAP1 system highlight that CDDO acts specifically through NRF2 to exert AC16 cytoprotection from DOX whilst not promoting human lung and pancreatic cancer cell line viability. Via RNA-seq analysis, we reveal that CDDO dampens DOX-mediated effects on p53 signalling, apoptosis and ferroptosis. This study provides novel insight into NRF2 dynamics in the widely utilised AC16 cells whilst further elucidating the molecular mechanisms contributing to DOX cardiotoxicity and potential NRF2-orchestrated defence. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=106 SRC="FIGDIR/small/675420v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@18c0bb5org.highwire.dtl.DTLVardef@154c707org.highwire.dtl.DTLVardef@d6c127org.highwire.dtl.DTLVardef@122ef0d_HPS_FORMAT_FIGEXP M_FIG C_FIG

pharmacology and toxicology↗

bioRxiv2025

Adult organotypic brain slice cultures recapitulate extracellular matrix remodelling in haemorrhagic stroke

1.Haemorrhagic stroke is a devastating condition characterised by vessel rupture and free blood within the brain parenchyma or cerebrospinal fluid (CSF) filled spaces. Across the major subtypes of haemorrhagic stroke (subarachnoid, intracerebral, and intraventricular haemorrhages), the presence of blood in the CSF generates significant tissue damage in the first 72 hours after the event, known as early brain injury (EBI). EBI includes neuroinflammation, blood-brain barrier breakdown and dysregulation of extracellular matrix (ECM) dynamics. ECM dysfunction has been shown to trigger fibrosis of the cortical blood vessels, limiting normal CSF circulation and resulting in the buildup of metabolic waste or the development of post-haemorrhagic hydrocephalus. Limiting or preventing this fibrosis may therefore reduce the rate of morbidity experienced by survivors, providing a potential avenue for non-surgical treatment to reduce secondary brain injury post-stroke. Despite this, current in vivo approaches fail to differentiate between the effect of blood products and secondary consequences including intracranial pressure (ICP) elevation and mass effect. Here, we describe an adult rat organotypic brain slice culture (OBSC) model of haemorrhagic stroke which enables the identification of the effect of blood products on ECM dysregulation. We demonstrate the distribution of key cell types across a time course of 0, 3 and 7 days in culture, indicating that such cultures are viable for a minimum of 7 days. Using immunofluorescence staining, Western blotting and RNA sequencing, we show that exposure of OBSCs to lysed blood markedly increases ECM deposition around cortical blood vessels. This is accompanied by dysregulation of ECM regulatory genes and upregulation of inflammation and oxidative stress-related genes, successfully recapitulating the changes seen in human stroke survivors. This versatile ex vivo model provides a translational platform to further understanding of haemorrhagic stroke pathophysiology and develop or trial novel therapeutics prior to progression to in vivo stroke studies.

neuroscience↗