👤 Dan Donnelly

Elevated lipoprotein(a) [Lp(a)] is an independent, causal risk factor for atherosclerotic cardiovascular disease (ASCVD), yet testing remains low. As our health system has expanded its efforts to increase Lp(a) awareness, we evaluated testing rates and their impact on care. Lp(a) testing rates were collected through electronic health record queries between 1/1/2022 to 12/31/2024. Baseline demographics, ASCVD status, Lp(a) testing rates by specialty, lipid lowering therapy (LLT) prescriptions and number of cardiology referrals were collected. 450,412 outpatients had ≥1 lipid panel order and 3.7 % ( While Lp(a) testing was low, it increased substantially over time. High risk Lp(a) levels were found irrespective of ASCVD status and were associated with more aggressive treatment. Systematic strategies to increase Lp(a) awareness and testing are warranted to mitigate cardiovascular risk. Show less

We examined whether wake-time movement composition was associated with weight loss maintenance among individuals who experienced clinically meaningful weight loss (> 5% of initial weight) using compositional data analysis. This was a secondary analysis from a behavioral weight loss maintenance intervention on weight regain over 12 months following clinically meaningful 3-month weight loss. Body weight was assessed at baseline, after weight loss (3 months), and at end of intervention (15 months). Wake-time behaviors (sedentary time [ST], light physical activity [LPA], and moderate-to-vigorous PA [MVPA]) were assessed at two time points during the maintenance intervention using accelerometry. Compositional data analysis was used to examine associations between wake-time movement composition and weight regain (kg). Among 153 individuals (80.4% female, 69.9% White), wake-time movement composition was related to weight regain (p = 0.001). MVPA was negatively associated with weight regain (p's < 0.05). Reallocating 10 min/day from ST or LPA to MVPA was associated with less weight regain (ST: -0.32 kg [-0.53, -0.12]; LPA: -0.37 kg [-0.59, -0.15]). Individuals who maintained clinically meaningful weight loss and those who did not differed in wake-time movement composition, driven by MVPA (36.1 vs. 24.3 min/day). The composition of wake-time behaviors, specifically MVPA, reduces weight regain after clinically meaningful weight loss in a behavioral weight loss maintenance intervention. ClinicalTrials.gov identifier: NCT01664715. Show less

Amyloid precursor protein (APP) is a brain-rich, single pass transmembrane protein that is proteolytically processed into multiple products, including amyloid-beta (Aβ), a major driver of Alzheimer disease (AD). Although both overexpression of APP and exogenously delivered Aβ lead to changes in sleep, whether APP processing plays an endogenous role in regulating sleep is unknown. Here, we demonstrate that APP processing into Aβ40 and Aβ42 is conserved in zebrafish and then describe sleep/wake phenotypes in loss-of-function Show less

Genome-wide association studies have so far identified 56 loci associated with risk of coronary artery disease (CAD). Many CAD loci show pleiotropy; that is, they are also associated with other diseases or traits. This study sought to systematically test if genetic variants identified for non-CAD diseases/traits also associate with CAD and to undertake a comprehensive analysis of the extent of pleiotropy of all CAD loci. In discovery analyses involving 42,335 CAD cases and 78,240 control subjects we tested the association of 29,383 common (minor allele frequency >5%) single nucleotide polymorphisms available on the exome array, which included a substantial proportion of known or suspected single nucleotide polymorphisms associated with common diseases or traits as of 2011. Suggestive association signals were replicated in an additional 30,533 cases and 42,530 control subjects. To evaluate pleiotropy, we tested CAD loci for association with cardiovascular risk factors (lipid traits, blood pressure phenotypes, body mass index, diabetes, and smoking behavior), as well as with other diseases/traits through interrogation of currently available genome-wide association study catalogs. We identified 6 new loci associated with CAD at genome-wide significance: on 2q37 (KCNJ13-GIGYF2), 6p21 (C2), 11p15 (MRVI1-CTR9), 12q13 (LRP1), 12q24 (SCARB1), and 16q13 (CETP). Risk allele frequencies ranged from 0.15 to 0.86, and odds ratio per copy of the risk allele ranged from 1.04 to 1.09. Of 62 new and known CAD loci, 24 (38.7%) showed statistical association with a traditional cardiovascular risk factor, with some showing multiple associations, and 29 (47%) showed associations at p < 1 × 10 We identified 6 loci associated with CAD at genome-wide significance. Several CAD loci show substantial pleiotropy, which may help us understand the mechanisms by which these loci affect CAD risk. Show less

Myocardial infarction (MI), a leading cause of death around the world, displays a complex pattern of inheritance. When MI occurs early in life, genetic inheritance is a major component to risk. Previously, rare mutations in low-density lipoprotein (LDL) genes have been shown to contribute to MI risk in individual families, whereas common variants at more than 45 loci have been associated with MI risk in the population. Here we evaluate how rare mutations contribute to early-onset MI risk in the population. We sequenced the protein-coding regions of 9,793 genomes from patients with MI at an early age (≤50 years in males and ≤60 years in females) along with MI-free controls. We identified two genes in which rare coding-sequence mutations were more frequent in MI cases versus controls at exome-wide significance. At low-density lipoprotein receptor (LDLR), carriers of rare non-synonymous mutations were at 4.2-fold increased risk for MI; carriers of null alleles at LDLR were at even higher risk (13-fold difference). Approximately 2% of early MI cases harbour a rare, damaging mutation in LDLR; this estimate is similar to one made more than 40 years ago using an analysis of total cholesterol. Among controls, about 1 in 217 carried an LDLR coding-sequence mutation and had plasma LDL cholesterol > 190 mg dl(-1). At apolipoprotein A-V (APOA5), carriers of rare non-synonymous mutations were at 2.2-fold increased risk for MI. When compared with non-carriers, LDLR mutation carriers had higher plasma LDL cholesterol, whereas APOA5 mutation carriers had higher plasma triglycerides. Recent evidence has connected MI risk with coding-sequence mutations at two genes functionally related to APOA5, namely lipoprotein lipase and apolipoprotein C-III (refs 18, 19). Combined, these observations suggest that, as well as LDL cholesterol, disordered metabolism of triglyceride-rich lipoproteins contributes to MI risk. Show less

Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are important regulators of insulin secretion, and their functional loss is an early characteristic of type 2 diabetes mellitus (T2DM). Pharmacological levels of GLP-1, but not GIP, can overcome this loss. GLP-1 and GIP exert their insulinotropic effects through their respective receptors expressed on pancreatic β-cells. Both the GLP-1 receptor (GLP-1R) and the GIP receptor (GIPR) are members of the secretin family of G protein-coupled receptors (GPCRs) and couple positively to adenylate cyclase. We compared the signalling properties of these two receptors to gain further insight into why GLP-1, but not GIP, remains insulinotropic in T2DM patients. GLP-1R and GIPR were transiently expressed in HEK-293 cells, and basal and ligand-induced cAMP production were investigated using a cAMP-responsive luciferase reporter gene assay. Arrestin3 (Arr3) recruitment to the two receptors was investigated using enzyme fragment complementation, confocal microscopy and fluorescence resonance energy transfer (FRET). GIPR displayed significantly higher (P<0.05) ligand-independent activity than GLP-1R. Arr3 displayed a robust translocation to agonist-stimulated GLP-1R but not to GIPR. These observations were confirmed in FRET experiments, in which GLP-1 stimulated the recruitment of both GPCR kinase 2 (GRK2) and Arr3 to GLP-1R. These interactions were not reversed upon agonist washout. In contrast, GIP did not stimulate recruitment of either GRK2 or Arr3 to its receptor. Interestingly, arrestin remained at the plasma membrane even after prolonged (30 min) stimulation with GLP-1. Although the GLP-1R/arrestin interaction could not be reversed by agonist washout, GLP-1R and arrestin did not co-internalise, suggesting that GLP-1R is a class A receptor with regard to arrestin binding. GIPR displays higher basal activity than GLP-1R but does not effectively recruit GRK2 or Arr3. Show less

In sequencing studies of common diseases and quantitative traits, power to test rare and low frequency variants individually is weak. To improve power, a common approach is to combine statistical evidence from several genetic variants in a region. Major challenges are how to do the combining and which statistical framework to use. General approaches for testing association between rare variants and quantitative traits include aggregating genotypes and trait values, referred to as 'collapsing', or using a score-based variance component test. However, little attention has been paid to alternative models tailored for protein truncating variants. Recent studies have highlighted the important role that protein truncating variants, commonly referred to as 'loss of function' variants, may have on disease susceptibility and quantitative levels of biomarkers. We propose a Bayesian modelling framework for the analysis of protein truncating variants and quantitative traits. Our simulation results show that our models have an advantage over the commonly used methods. We apply our models to sequence and exome-array data and discover strong evidence of association between low plasma triglyceride levels and protein truncating variants at APOC3 (Apolipoprotein C3). Software is available from http://www.well.ox.ac.uk/~rivas/mamba Show less

The 17q21.31 inversion polymorphism exists either as direct (H1) or inverted (H2) haplotypes with differential predispositions to disease and selection. We investigated its genetic diversity in 2,700 individuals, with an emphasis on African populations. We characterize eight structural haplotypes due to complex rearrangements that vary in size from 1.08-1.49 Mb and provide evidence for a 30-kb H1-H2 double recombination event. We show that recurrent partial duplications of the KANSL1 gene have occurred on both the H1 and H2 haplotypes and have risen to high frequency in European populations. We identify a likely ancestral H2 haplotype (H2') lacking these duplications that is enriched among African hunter-gatherer groups yet essentially absent from West African populations. Whereas H1 and H2 segmental duplications arose independently and before human migration out of Africa, they have reached high frequencies recently among Europeans, either because of extraordinary genetic drift or selective sweeps. Show less

To establish that human adipocytes express functional glucose-dependent insulinotropic peptide (GIP) receptors and in particular the regulation of GIP receptor (GIPR) expression in the context of the dynamic process of adipocyte differentiation. A combination of semiquantitative real-time PCR and measurement of GIP-stimulated cAMP accumulation was used to establish the expression and functional coupling of GIPRs during in vitro differentiation of human Simpson-Golabi-Behmel syndrome (SGBS) preadipocytes. Semiquantitative real-time PCR revealed that GIPR expression was substantially increased by day 4 of differentiation, reaching a maximum around 6-8 days (approximately 200-fold increase above undifferentiated cells, n=2). We also analysed the expression of the adipocyte fatty acid binding protein (FABP4) to relate GIPR expression to a molecular differentiation marker of adipogenesis. FABP4 expression was barely detectable in undifferentiated cells. However, following exposure to adipogenic medium, FABP4 expression gradually increased, with a maximal expression level around 10 days (approximately 1,600,000-fold increase above undifferentiated cells, n=2). Thus, the increases in GIPR mRNA during adipogenesis occur earlier than FABP4, suggesting that it might represent a gene expressed early in terminal differentiation and thus plays a role in fat droplet formation. A unit of 1 microM GIP failed to raise intracellular cAMP levels above basal levels in undifferentiated cells (n=3). In stark contrast, the 9-day differentiated cells produced a robust concentration-dependent increase in cAMP accumulation following stimulation with GIP, with an EC(50) value of 2.3 nM (n=3). The maximal response represented a 9-34-fold increase in cAMP accumulation above basal levels. This study demonstrates that GIPRs are expressed by human adipocytes, both GIPR mRNA and functional receptor expression being present in differentiated adipocytes but not in preadipocytes. Further investigation into the functional effects of GIP on differentiated SGBS cells could help towards understanding exactly how GIP regulates fat accumulation in human adipocytes. Show less

In selecting a method to produce a recombinant protein, a researcher is faced with a bewildering array of choices as to where to start. To facilitate decision-making, we describe a consensus 'what to try first' strategy based on our collective analysis of the expression and purification of over 10,000 different proteins. This review presents methods that could be applied at the outset of any project, a prioritized list of alternate strategies and a list of pitfalls that trip many new investigators. Show less