Publications by authors named "Kerrin Small"

Cardiovascular disease progression is characterised by the dysregulation of lipid metabolism and pro-atherogenic effects of adipose tissue signalling. Recent findings from the analysis of transcriptomic data in bulk tissue has enabled these insights and revealed important changes in gene expression. However, few studies have explored these molecular mechanisms before the onset of cardiovascular disease.

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Background: Perfluorooctanoic acid (PFOA) and Perfluorooctanesulfonic Acid (PFOS) are synthetic substances with long half-lives. Their presence is widespread and pervasive, and they are noted for their environmental persistence. Research has shown these chemicals to be associated with dyslipidaemia, although few studies have considered the long-term associations in the general population.

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Heavy metals in our direct environment have profound effects on human health and while some are essential for life, others can be toxic. In vivo studies often focus on clinical features caused by overexposure to, or by deprivation of a heavy metal. However, to understand the cellular impact of heavy metals on health, studies in healthy volunteers before symptom onset are needed.

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Complete characterization of the genetic effects on gene expression is needed to elucidate tissue biology and the etiology of complex traits. In the present study, we analyzed 2,344 subcutaneous adipose tissue samples and identified 34,774 conditionally distinct expression quantitative trait locus (eQTL) signals at 18,476 genes. Over half of eQTL genes exhibited at least two eQTL signals.

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  • Genome-wide association studies have found numerous genetic loci linked to glycemic traits, but connecting these loci to specific genes and biological pathways remains a challenge.
  • Researchers conducted meta-analyses of exome-array studies across four glycemic traits, analyzing data from over 144,000 participants, which led to the identification of coding variant associations in more than 60 genes.
  • The study revealed significant pathways related to insulin secretion, zinc transport, and fatty acid metabolism, enhancing understanding of glycemic regulation and making data available for further research.
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Whole-skin DNA methylation variation has been implicated in several diseases, including melanoma, but its genetic basis has not yet been fully characterized. Using bulk skin tissue samples from 414 healthy female UK twins, we performed twin-based heritability and methylation quantitative trait loci (meQTL) analyses for >400,000 DNA methylation sites. We find that the human skin DNA methylome is on average less heritable than previously estimated in blood and other tissues (mean heritability: 10.

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  • Meiotic recombination is crucial for genetic diversity, involving both crossovers and non-crossover events that lead to gene conversion.
  • Researchers used long sequencing reads from sperm samples to analyze recombination events, highlighting variability between and within male donors.
  • The study found non-crossover gene conversions often occur near PRDM9 binding sites, suggesting two distinct mechanisms: one common, linked to PRDM9, and another rarer, associated with complex genetic events.
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  • Scientists looked at the timing of when girls start their periods (called menarche) and how it can affect their health later in life.
  • They studied about 800,000 women and found over a thousand genetic signals that influence when menstruation starts.
  • Some women have a much higher chance of starting their periods too early or too late based on their genetic makeup, suggesting that genes play a big role in this process!
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Objectives: Systemic lupus erythematosus (SLE) shows a marked female bias in prevalence. X chromosome inactivation (XCI) is the mechanism which randomly silences one X chromosome to equalise gene expression between 46, XX females and 46, XY males. Though XCI is expected to result in a random pattern of mosaicism across tissues, some females display a significantly skewed ratio in immune cells, termed XCI-skew.

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The objective assessment of habitual (poly)phenol-rich diets in nutritional epidemiology studies remains challenging. This study developed and evaluated the metabolic signature of a (poly)phenol-rich dietary score (PPS) using a targeted metabolomics method comprising 105 representative (poly)phenol metabolites, analyzed in 24 h of urine samples collected from healthy volunteers. The metabolites that were significantly associated with PPS after adjusting for energy intake were selected to establish a metabolic signature using a combination of linear regression followed by ridge regression to estimate penalized weights for each metabolite.

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Complete characterization of the genetic effects on gene expression is needed to elucidate tissue biology and the etiology of complex traits. Here, we analyzed 2,344 subcutaneous adipose tissue samples and identified 34K conditionally distinct expression quantitative trait locus (eQTL) signals in 18K genes. Over half of eQTL genes exhibited at least two eQTL signals.

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Background: B vitamins such as folate (B9), B6, and B12 are key in one carbon metabolism, which generates methyl donors for DNA methylation. Several studies have linked differential methylation to self-reported intakes of folate and B12, but these estimates can be imprecise, while metabolomic biomarkers can offer an objective assessment of dietary intakes. We explored blood metabolomic biomarkers of folate and vitamins B6 and B12, to carry out epigenome-wide analyses across up to three European cohorts.

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  • Scientists are studying how genes are turned on and off in the human brain to understand brain diseases better.
  • They used special techniques to look at where and how genes work in different parts of brain cells.
  • Their research found that many important gene changes happen in the brain's cytoplasm (the part of the cell outside the nucleus) and that these changes are often connected to how brain cells communicate with each other.
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Pubertal timing varies considerably and has been associated with a range of health outcomes in later life. To elucidate the underlying biological mechanisms, we performed multi-ancestry genetic analyses in ~800,000 women, identifying 1,080 independent signals associated with age at menarche. Collectively these loci explained 11% of the trait variance in an independent sample, with women at the top and bottom 1% of polygenic risk exhibiting a ~11 and ~14-fold higher risk of delayed and precocious pubertal development, respectively.

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Postzygotic mutations (PZMs) begin to accrue in the human genome immediately after fertilization, but how and when PZMs affect development and lifetime health remain unclear. To study the origins and functional consequences of PZMs, we generated a multitissue atlas of PZMs spanning 54 tissue and cell types from 948 donors. Nearly half the variation in mutation burden among tissue samples can be explained by measured technical and biological effects, and 9% can be attributed to donor-specific effects.

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X-chromosome inactivation (XCI) silences one X in female cells to balance sex-differences in X-dosage. A subset of X-linked genes escape XCI, but the extent to which this phenomenon occurs and how it varies across tissues and in a population is as yet unclear. To characterize incidence and variability of escape across individuals and tissues, we conducted a transcriptomic study of escape in adipose, skin, lymphoblastoid cell lines and immune cells in 248 healthy individuals exhibiting skewed XCI.

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Proton pump inhibitors (PPIs) are among the most used drugs in the UK. PPI use has been associated with decreased bone mineral density (BMD) and increased fracture risk, although these results have been inconsistent. We hypothesized that PPI could modulate BMD by altering gut and/or host systemic metabolic environments.

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Background: Ageing is a heterogenous process characterised by cellular and molecular hallmarks, including changes to haematopoietic stem cells and is a primary risk factor for chronic diseases. X chromosome inactivation (XCI) randomly transcriptionally silences either the maternal or paternal X in each cell of 46, XX females to balance the gene expression with 46, XY males. Age acquired XCI-skew describes the preferential selection of cells across a tissue resulting in an imbalance of XCI, which is particularly prevalent in blood tissues of ageing females, and yet its clinical consequences are unknown.

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  • Obesity in humans and mice is linked to increased levels of the hormones GDF15 and FGF21, which are associated with weight loss and improved metabolism but their specific roles in the context of overfeeding are not fully understood.
  • Research using knockout mouse models and human tissue analysis reveals that both GDF15 and FGF21 primarily come from the liver during obesity, not from fat or muscle tissues.
  • Deleting both GDF15 and FGF21 does not lead to more weight gain on a high-fat diet but increases liver fat and insulin resistance compared to isolating the deletion of GDF15, indicating that these hormones help manage liver stress during overfeeding.
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Background: There is considerable evidence for the importance of the DNA methylome in metabolic health, for example, a robust methylation signature has been associated with body mass index (BMI). However, visceral fat (VF) mass accumulation is a greater risk factor for metabolic disease than BMI alone. In this study, we dissect the subcutaneous adipose tissue (SAT) methylome signature relevant to metabolic health by focusing on VF as the major risk factor of metabolic disease.

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  • COVID-19 severity is influenced by various factors such as age and obesity, but the exact mechanisms behind these risks remain unclear.
  • A meta-analysis involving 1,471 participants examined the relationship between genetic and phenotypic factors and the expression of ACE2 in adipose tissue, which is critical for SARS-CoV-2 entry into cells.
  • Findings revealed that lower ACE2 expression is linked to poorer cardio-metabolic health, such as type 2 diabetes and obesity, suggesting that reduced ACE2 may play a role in worsening COVID-19 outcomes among individuals with these health issues.
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Large-scale gene sequencing studies for complex traits have the potential to identify causal genes with therapeutic implications. We performed gene-based association testing of blood lipid levels with rare (minor allele frequency < 1%) predicted damaging coding variation by using sequence data from >170,000 individuals from multiple ancestries: 97,493 European, 30,025 South Asian, 16,507 African, 16,440 Hispanic/Latino, 10,420 East Asian, and 1,182 Samoan. We identified 35 genes associated with circulating lipid levels; some of these genes have not been previously associated with lipid levels when using rare coding variation from population-based samples.

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Context: Biological and translational insights from large-scale, array-based genetic studies of fat distribution, a key determinant of metabolic health, have been limited by the difficulty in linking predominantly noncoding variants to specific gene targets. Rare coding variant analyses provide greater confidence that a specific gene is involved, but do not necessarily indicate whether gain or loss of function (LoF) would be of most therapeutic benefit.

Objective: This work aimed to identify genes/proteins involved in determining fat distribution.

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