Biology subjects

Southwood, M.

Publications and source records attributed to Southwood, M..

5 recordsLinked to original sources

bioRxiv2026

YBX3 overexpression in mesothelioma drives aberrant cell proliferation

Malignant pleural mesothelioma (MpM) is a lethal tumour closely linked to asbestos exposure and is a cancer of unmet clinical need with no known oncogenic drivers. Recent advancements in technologies to identify RNA-binding proteins (RBPs) has uncovered an emerging role for RBP-RNA interactions in cancer progression and we therefore assessed changes in the RBPome of patient-derived MpM cell lines. We identify over 350 RBPs showing altered RNA binding, with functions consistent with key cancer hallmarks, and discovered YBX3 as a potential oncoprotein driving cell proliferation in MpM. Mechanistically we show the impact of YBX3 on cell growth is achieved through its control of the expression of the amino acid transporter SLC7A5/LAT1, with increased amino acid uptake increasing protein synthesis rates. Notably, we show the inhibition of cell growth by YBX3 deletion is recapitulated by the clinically-relevant SLC7A5/LAT1 inhibitor JPH203. Finally, we demonstrate that JPH203 sensitizes MpM cells to radiotherapy, which could provide a promising therapeutic strategy for MpM. TeaserHigher levels of YBX3 expression in mesothelioma increases cell proliferation and protein synthesis rates by upregulation of amino acid uptake.

molecular biology↗

bioRxiv2026

Interrogation of the glycolytic axis in pulmonary arterial hypertension models and how modifying these can lead to potential therapeutic options.

IntroductionPulmonary arterial hypertension (PAH) describes diseases characterized by increased pulmonary vessel pressures that lead to right ventricular failure and death if left untreated. Dysregulated metabolic function has been reported in endothelial cells from PAH patients. Healthy endothelial cells can rapidly shift from quiescence to proliferative and apoptotic states, partly due to a greater utilization of glycolysis for ATP production, rather than the slower oxidative phosphorylation more commonly relied on by other cell types. However, in PAH patients, pulmonary artery endothelial cells demonstrate an even greater shift towards glycolytic ATP production. This phenomenon, which was first described in cancer as the Warburg effect, is an adaptation for optimizing both energy production and biosynthetic processes for maximum proliferative potential. Hypothesis and MethodsWe hypothesize that targeting the PKM2 axis in endothelial cells may shift the balance to favor oxidative phosphorylation, in effect reversing the Warburg effect; and that this would have beneficial effects in cell and rodent models of PAH. To this end we have tested TEPP-46, an allosteric PKM2 activator that stabilizes the tetrameric form, blocking its translocation into the nucleus and increasing canonical enzymatic activity, in blood outgrowth endothelial cells (BOECs) and in a rat Sugen-hypoxia model. ResultsTEPP-46 treatment reduced levels of nuclear PKM2 (the homodimer form which promotes anabolic effects and proliferation). Cytoplasmic levels of PKM2 and levels of PKM1 were unaffected. Exposure to TEPP-46 lowered levels of polypyrimidine tract-binding protein 1 (PTPB1), which controls alternative splicing of the PKM gene to promote PKM2 expression; and reduced LDHA, which converts pyruvate to lactate, preventing its utilization for oxidative phosphorylation. In the Sugen-hypoxia rat model, administration of TEPP-46 significantly ameliorated the elevated right ventricular systolic pressures, reduced the loss of body weight and increased survival. The increased muscularization of the smaller blood arteries and arterioles in the lungs of rats due to Sugen-hypoxia were also improved by concurrent administration of TEPP-46. ConclusionWe have shown that TEPP-46 treatment reduces nuclear PKM2 and represses PKM2-driven gene expression, with the functional effect of ameliorating the Sugen-hypoxia phenotype. This suggests that antagonizing the Warburg effect may offer a novel therapeutic avenue for PAH.

physiology↗

bioRxiv2025

Interleukin-6 is critical in the development of gcn2-mutation associated pulmonary vascular disease in mice

Biallelic mutations in eukaryotic translation initiation factor 2 kinase 4, EIF2AK4 (which encodes general control nonderepressible 2, GCN2) underpin heritable forms of pulmonary veno-occlusive disease (PVOD), a rare and fatal form of pulmonary hypertension. The mechanisms linking these are mostly uncharacterised. We demonstrate for the first time that homozygous loss of gcn2 is sufficient to cause mild pulmonary hypertension in mice. Single-cell transcriptomics of mouse lungs identified adventitial fibroblasts as having the greatest GCN2-dependent transcriptional differences, implicating them as key players in this model of PVOD. The most significantly upregulated pathways in gcn2-/- adventitial fibroblasts were inflammatory. Therefore, we went on to demonstrate a pro-inflammatory phenotype in gcn2-/- mouse embryonic fibroblasts and gcn2-/- mice. In a novel murine model of pulmonary hypertension induced by exposure to mitomycin C, deletion of interleukin-6 rescued the pulmonary vascular phenotype. When chronically exposed to lipopolysaccharide, the pulmonary hypertensive phenotype of gcn2-/- mice is exaggerated. Genetic ablation of interleukin-6 completely rescues both the baseline and LPS-exaggerated pulmonary hypertensive phenotype. Targeting Il6-dependent pathways may be useful in treating this deadly disease.

pathology↗

bioRxiv2020

Circulating BMP9 protects the pulmonary endothelium during inflammation-induced lung injury in mice

RationalePulmonary endothelial permeability contributes to the high-permeability pulmonary edema that characterizes acute respiratory distress syndrome (ARDS), which carries a high mortality. Circulating bone morphogeneic protein 9 (BMP9) is emerging as an important regulator of pulmonary vascular homeostasis. ObjectiveTo determine whether endogenous BMP9 plays a role in preserving pulmonary endothelial integrity, and whether loss of endogenous BMP9 occurs during lipopolysacharride (LPS)-induced lung inflammation and permeability. MethodsA BMP9-neutralizing antibody was administrated to healthy adult mice and lung vasculature was examined. Potential mechanisms were delineated by transcript analysis in human primary lung endothelial cells. Impact of BMP9 was evaluated in a murine acute lung injury model induced by inhaled LPS. Levels of BMP9 were measured in plasma from patients with sepsis and endotoxemic mice. Main ResultsSubacute neutralization of endogenous BMP9 in mice resulted in increased lung vascular permeability, interstitial edema and neutrophil extravasation. In lung endothelial cells, BMP9 regulated a programme of gene expression and pathways controlling vascular permeability and cell membrane integrity. Augmentation of BMP9 signalling in mice with exogenous BMP9 prevented inhaled LPS-caused lung injury and edema. In endotoxemic mice, endogenous BMP9 levels were markedly reduced, due to a transient reduction in hepatic BMP9 mRNA expression and increased elastase activity in plasma. In human sepsis patients, circulating levels of BMP9 were also markedly reduced. ConclusionsEndogenous circulating BMP9 is a pulmonary endothelial protective factor, down-regulated during inflammation. Supplementation with exogenous BMP9 offers a potential therapy to prevent increased pulmonary endothelial permeability in the setting of lung injury. Short summaryO_ST_ABSScientific Knowledge on the SubjectC_ST_ABSIncreased pulmonary endothelial permeability is a major factor in the development of acute respiratory distress syndrome (ARDS). Evidence is emerging that circulating BMP9, secreted from the liver, might protect the pulmonary endothelium from injury. For example, loss of BMP9 levels or signalling receptor contributes to the development of pulmonary arterial hypertension. The role of endogenous BMP9 in endothelial permeability remains unclear. What This Study Adds to the FieldHere we show that subacute neutralization of endogenous BMP9 leads to lung vascular injury, including enhanced permeability and neutrophil extravasation. BMP9 levels were markedly reduced in the setting of inflammation in mice and humans. Conversely, exogenous supplementation of BMP9 protected the lung from LPS-induced injury. This study suggests that exogenous BMP9 could offer a novel approach to prevent increased pulmonary endothelial permeability in the setting of lung injury and ARDS.

physiology↗

bioRxiv2017

Novel causative genes for heritable pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a rare disorder with a poor prognosis. Deleterious variation within components of the transforming growth factor-{beta} pathway, particularly the bone morphogenetic protein type 2 receptor (BMPR2), underlie most heritable forms of PAH. Since the missing heritability likely involves genetic variation confined to small numbers of cases, we performed whole genome sequencing in 1038 PAH index cases and 6385 PAH-negative control subjects. Case-control analyses revealed significant overrepresentation of rare variants in novel genes, namely ATP13A3, AQP1 and SOX17, and provided independent validation of a critical role for GDF2 in PAH. We provide evidence for familial segregation of mutations in SOX17 and AQP1 with PAH. Mutations in GDF2, encoding a BMPR2 ligand, led to reduced secretion from transfected cells. In addition, we identified pathogenic mutations in the majority of previously reported PAH genes, and provide evidence for further putative genes. Taken together these findings provide new insights into the molecular basis of PAH and indicate unexplored pathways for therapeutic intervention.

genetics↗