Biology subjects

Davies, W.

Publications and source records attributed to Davies, W..

4 recordsLinked to original sources

bioRxiv2026

Steroid sulfatase deficiency increases the frequency and persistence of ventricular arrhythmias in mice

BackgroundEmerging evidence in humans has linked Xp22.31 genetic deletions to an increased risk of stress-induced arrhythmias, and association analysis across Xp22.31 has shown enrichment for atrial fibrillation genetic risk variants around STS (steroid sulfatase). MethodsWe compared heart rhythm in homozygous STS-knockout (STS-KO) adult mice (n=19) to wildtype (WT) mice (n=11) under baseline (Tyrodes solution), and {beta}-adrenergic stimulation (stress), conditions using ex vivo perfused-heart electrocardiography (ECG). Ventricular ectopic beats (VEBs) were manually-identified, and rhythm abnormalities were quantified using a semi-automated approach. ResultsAt baseline, the groups displayed comparable sinus cycle length and ECG intervals; all WT hearts showed stable sinus rhythm, whereas [~]30% of STS-KO hearts developed spontaneous VEBs. WT hearts typically maintained steady rhythm under {beta}-adrenergic stimulation; in contrast, [~]60% of STS-KO hearts displayed VEBs. Under baseline and stimulated conditions the QRS interval was greater during VEBs than normal beats in STS-KO hearts, consistent with a ventricular origin. We identified a higher frequency of any abnormal beats in STS-KO hearts than in WT hearts under baseline (1.9{+/-}0.7% vs. 0.3{+/-}0.1%, p=0.038) and stimulated (5.3{+/-}2.2% vs. 0.5{+/-}0.3%, p=0.047) conditions. Under stimulated conditions, abnormal beats only occurred singly in WT hearts, whereas in STS-KO hearts, [~]50% of the time they occurred in runs of two or more. ConclusionSTS deficiency in mice predisposes to arrhythmias, and the STS-KO mouse represents a tractable model for mechanistic investigation. These data support the contention that STS activity influences arrhythmic vulnerability in humans and that STS should be considered for inclusion in arrhythmia-related gene panels.

physiology↗

bioRxiv2026

Physiological and behavioural characterisation of a novel steroid sulfatase-deficient mouse

BackgroundSteroid sulfatase (STS) cleaves sulfate groups from steroid hormones. In humans, STS deficiency is associated with X-linked ichthyosis (a dermatological disorder), neurodevelopmental/mood conditions, and cardiac arrhythmias. Until recently, no single-gene knockout mammalian model existed to investigate these associations; previous work in such a model has been limited to skin phenotypes. MethodsWe generated a novel C57BL/6J mouse model with a deletion in critical exon 2 of Sts. We then examined gene expression and enzyme activity in liver and brain samples of homozygous mice, and assessed the breeding performance and health of male and female deletion-carriers. Subsequently, we compared performance across a range of behavioural paradigms in wildtype and homozygous male and female mice: elevated plus maze, open field, rotarod, spontaneous alternation, and acoustic startle/prepulse inhibition. We also investigated serum steroid hormone levels by liquid chromatography-mass spectrometry and measured heart weights and two morphological indices (bodyweight/tibia length) post mortem. ResultsHomozygous mice almost completely lacked STS expression/activity. Genetically-altered mice exhibited grossly-normal breeding performance, health, and endocrinology. Homozygous mice were more active, and had higher normalised heart weights, than wildtype mice. We also found significant genotype x sex interactions on bodyweight, and on two behavioural measures (potentially reflecting lower anxiety in homozygous males and heightened anxiety in homozygous females). ConclusionsThe Sts-deletion mouse represents an experimentally-tractable model in which to identify and characterise phenotypes associated with STS deficiency. The mechanistic basis of the genotype-phenotype associations described here requires further investigation, and whether such associations translate to humans remains to be tested.

animal behavior and cognition↗

bioRxiv2019

Brain gene expression in a novel mouse model of postpartum mood disorder

IntroductionSteroid sulfatase (STS) is an enzyme which cleaves sulfate groups from a variety of steroid hormones, thereby altering their activity and solubility. The expression and activity of STS is increased in female mammalian tissues (including brain) during late pregnancy and into the postpartum period. STS-deficient human and mouse mothers (as a consequence of genetic mutation or acute pharmacological manipulation) show evidence for elevated psychopathology and abnormal behaviour respectively in the postpartum period. In mice, these behavioural effects can be partially normalised through administration of the antipsychotic ziprasidone. MethodsTo explore the neurobiology underlying these postpartum behavioural effects, we compared whole brain gene expression by microarray in behaviourally-defined new mouse mothers acutely administered the STS inhibitor 667-Coumate (10mg/kg p.o.) or vehicle solution (n=12 per group); significant changes were followed-up with pathway analysis and quantitative polymerase chain reaction (qPCR). Finally, the effects of combined 667-Coumate and antipsychotic (ziprasidone) administration (0, 0.3 and 1.0mg/kg i.p.) on the brain expression of the most robustly differentially-expressed candidate genes was examined (n[≥]7 per group). ResultsSurprisingly, no significant gene expression changes were detected between vehicle and 667-Coumate-treated brains at a False Discovery Rate (FDR) corrected p<0.1. 1,081 unique expression changes were detected at a less-stringent cut-off of p<0.05, just two top hits were verified by qPCR, and pathway analysis indicated a significant enrichment of genes involved in olfactory transduction (corrected p-value=1.8x10-3). The expression of the two most robust differentially-expressed genes (Stoml3 and Cyp2g1) was not affected by ziprasidone administration. ConclusionsBehavioural abnormalities in new mothers in the postpartum period elicited as a result of STS deficiency are likely to be the culmination of many small gene expression changes. Our data are consistent with the idea that olfactory function is key to postpartum maternal behaviour in mice, and suggest that aberrant expression of olfactory system genes may partially underlie abnormal maternal behaviour in STS-deficient women.

neuroscience↗

bioRxiv2018

Sex differences in gene expression in the human fetal brain

Widespread structural, chemical and molecular differences have been reported between the male and female human brain. Although several neurodevelopmental disorders are more commonly diagnosed in males, little is known regarding sex differences in early human brain development. Here, we used RNA sequencing data from a large collection of human brain samples from the second trimester of gestation (N = 120) to assess sex biases in gene expression within the human fetal brain. In addition to 43 genes (102 Ensembl transcripts) transcribed from the Y-chromosome in males, we detected sex differences in the expression of 2558 autosomal genes (2723 Ensembl transcripts) and 155 genes on the X-chromosome (207 Ensembl transcripts) at a false discovery rate (FDR) < 0.1. Genes exhibiting sex-biased expression in human fetal brain are enriched for high-confidence risk genes for autism and other developmental disorders. Male-biased genes are enriched for expression in neural progenitor cells, whereas female-biased genes are enriched for expression in Cajal-Retzius cells and glia. All gene- and transcript-level data are provided as an online resource (available at http://fgen.psycm.cf.ac.uk/FBSeq1) through which researchers can search, download and visualize data pertaining to sex biases in gene expression during early human brain development.

genomics↗