The trans-ancestral genomic architecture of glycemic traits

LRP5 promotes adipose progenitor cell fitness and adipocyte insulin sensitivity

BACKGROUND

WNT signaling plays a key role in postnatal bone formation. Individuals with gain-of-function mutations in the WNT co-receptor LRP5 exhibit increased lower-body fat mass and potentially enhanced glucose metabolism, alongside high bone mass. However, the mechanisms by which LRP5 regulates fat distribution and its effects on systemic metabolism remain unclear. This study aims to explore the role of LRP5 in adipose tissue biology and its impact on metabolism.

METHODS

Metabolic assessments and imaging were conducted on individuals with gain- and loss-of-function LRP5 mutations, along with age- and BMI-matched controls. Mendelian randomization analyses were used to investigate the relationship between bone, fat distribution, and systemic metabolism. Functional studies and RNA sequencing were performed on abdominal and gluteal adipose cells with LRP5 knockdown.

RESULTS

Here we show that LRP5 promotes lower-body fat distribution and enhances systemic and adipocyte insulin sensitivity through cell-autonomous mechanisms, independent of its bone-related functions. LRP5 supports adipose progenitor cell function by activating WNT/β-catenin signaling and preserving valosin-containing protein (VCP)-mediated proteostasis. LRP5 expression in adipose progenitors declines with age, but gain-of-function LRP5 variants protect against age-related fat loss in the lower body.

CONCLUSIONS

Our findings underscore the critical role of LRP5 in regulating lower-body fat distribution and insulin sensitivity, independent of its effects on bone. Pharmacological activation of LRP5 in adipose tissue may offer a promising strategy to prevent age-related fat redistribution and metabolic disorders.

Assessing causal relationships between diabetes mellitus and idiopathic pulmonary fibrosis: a Mendelian randomisation study

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a disease of progressive lung scarring. There is a known association between diabetes mellitus (DM) and IPF, but it is unclear whether a causal relationship exists between these traits.

OBJECTIVES

The objectives of this study are to examine causal relationships among DM, diabetes-associated traits and IPF using a Mendelian randomisation approach.

METHODS

Two-sample MR approaches, including bidirectional inverse-variance weighted random effects and routine sensitivity models, used genetic variants identified from genome-wide association studies for type 1 diabetes (T1D), type 2 diabetes (T2D), glycated haemoglobin level (HbA1c), fasting insulin level and body mass index (BMI) to assess for causal effects of these traits on IPF. Further analyses using pleiotropy-robust and multivariable MR (MVMR) methods were additionally performed to account for trait complexity.

RESULTS

Results did not suggest that either T1D (OR=1.00, 95% CI 0.93 to 1.07, p=0.90) or T2D (1.02, 0.93 to 1.11, p=0.69) are in the causal pathway of IPF. No effects were suggested of HbA1c (1.19, 0.63 to 2.22, p=0.59) or fasting insulin level (0.60, 0.31 to 1.15, p=0.12) on IPF, but potential effects of BMI on IPF were indicated (1.44, 1.12 to 1.85, p=4.00×10-3). Results were consistent in MVMR, although no independent effects of T2D (0.91, 0.68 to 1.21, p=0.51) or BMI (1.01, 0.94 to 1.09, p=0.82) on IPF were observed when modelled together.

CONCLUSIONS

This study suggests that DM and IPF are unlikely to be causally linked. This comorbid relationship may instead be driven by shared risk factors or treatment effects.

Nuclear regulatory disturbances precede and predict the development of Type-2 diabetes in Asian populations

To identify biomarkers and pathways to Type-2 diabetes (T2D), a major global disease, we completed array-based epigenome-wide association in whole blood in 5,709 Asian people. We found 323 Sentinel CpGs (from 314 genetic loci) that predict future T2D. The CpGs reveal coherent, nuclear regulatory disturbances in canonical immune activation pathways, as well as metabolic networks involved in insulin signalling, fatty acid metabolism and lipid transport, which are causally linked to development of T2D. The CpGs have potential clinical utility as biomarkers. An array-based composite Methylation Risk Score (MRS) is predictive for future T2D (RR: 5.2 in Q4 vs Q1; P=7×10-25), and is additive to genetic risk. Targeted methylation sequencing revealed multiple additional CpGs predicting T2D, and synthesis of a sequencing-based MRS that is strongly predictive for T2D (RR: 8.3 in Q4 vs Q1; P=1.0×10-11). Importantly, MRS varies between Asian ethnic groups, in a way that explains a large fraction of the difference in T2D risk between populations. We thus provide new insights into the nuclear regulatory disturbances that precede development of T2D, and reveal the potential for sequence-based DNA methylation markers to inform risk stratification in diabetes prevention.

Dissecting the shared genetic architecture between nonalcoholic fatty liver disease and type 2 diabetes

Observational studies have reported a bidirectional correlation between nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes (T2D), but the shared genetic basis between the two conditions remains unclear. Using genome-wide association study (GWAS) summary data from European-ancestry populations, we examined the cross-trait genetic correlation and identified genomic overlaps and shared risk loci. We employed a latent causal variable model and Mendelian randomization (MR) analysis to infer causal relationships. Colocalization analysis and conditional/conjunctional false discovery rate (condFDR/conjFDR) were used to identify genomic overlaps and shared risk loci. Two-step MR analysis was utilized to identify potential mediators. We observed a strong positive genomic correlation between NAFLD and T2D (rg = 0.652, P = 5.67 × 10-6) and identified tissue-specific transcriptomic correlations in the pancreas, liver, skeletal muscle, subcutaneous adipose, and blood. Genetic enrichment was observed in NAFLD conditional on associations with T2D and vice versa, indicating significant polygenic overlaps. We found robust evidence for the causal effect of NAFLD on T2D, particularly insulin-related T2D, rather than vice versa. Colocalization analysis identified shared genomic regions between NAFLD and T2D, including GCKR, FTO, MAU2-TM6SF2, and PNPLA3-SAMM50. High-density lipoprotein cholesterol and insulin were partly mediated the association between NAFLD and T2D. These findings unveil a close genetic link between NAFLD and T2D, shedding light on the biological mechanisms connecting NAFLD progression to T2D.

Exploring the Associations of Obesity and Glycemic Traits with Retinal Vein Occlusion: A Univariate and Multivariable Mendelian Randomization Study

PURPOSE

To explore the genetic links between obesity, glycemic traits and retinal vein occlusion (RVO).

METHODS

Summary-level statistics for obesity and glycemic traits were extracted from publicly available genome-wide association studies (GWAS) of European participants in the IEU Open GWAS database. Genetic associations with clinically diagnosed RVO were obtained from the FinnGenresearch project (372 cases and 182,573 controls). Two-sample Mendelian randomization (MR) and multivariate MR (MVMR) analysis were performed to determine the total effect and direct effect, respectively.

RESULTS

After adjustment for the false discovery rate (FDR), the primary inverse-variance-weighted (IVW) methods indicated that the odds ratios of RVO increased with per 1-standard deviation increased in body mass index (BMI) (OR = 1.94, 95% CI: 1.23-3.08,p-FDR = 0.025), waist circumference (OR = 2.4, 95% CI: 1.36-4.24, p-FDR = 0.019), fasting glucose (OR = 5.01, 95% CI: 2-12.55, p-FDR = 0.0067) and two-hour glucose (OR = 3.17, 95% CI: 1.63-6.18,p-FDR = 0.0067). Higher whole-body fat-free mass (OR = 0.45, 95% CI: 0.26-0.8,p-FDR = 0.025) is a potential protective factor for RVO. In addition, the results of MVMR showed that BMI, whole-body fat-free mass, fasting glucose and two-hour glucose were independent factors that had a direct impact on the onset of RVO.

CONCLUSIONS

Our comprehensive MR analysis suggested significant genetic associations between BMI, whole-body fat-free mass, fasting glucose, two-hour glucose and RVO. This study highlighted the importance of weight, blood glucose management and physical activity for primary prevention and control of RVO.

Kidney multiome-based genetic scorecard reveals convergent coding and regulatory variants

Kidney dysfunction is a major cause of mortality, but its genetic architecture remains elusive. In this study, we conducted a multiancestry genome-wide association study in 2.2 million individuals and identified 1026 (97 previously unknown) independent loci. Ancestry-specific analysis indicated an attenuation of newly identified signals on common variants in European ancestry populations and the power of population diversity for further discoveries. We defined genotype effects on allele-specific gene expression and regulatory circuitries in more than 700 human kidneys and 237,000 cells. We found 1363 coding variants disrupting 782 genes, with 601 genes also targeted by regulatory variants and convergence in 161 genes. Integrating 32 types of genetic information, we present the "Kidney Disease Genetic Scorecard" for prioritizing potentially causal genes, cell types, and druggable targets for kidney disease.

Insights Into Causal Effects of Genetically Proxied Lipids and Lipid-Modifying Drug Targets on Cardiometabolic Diseases

BACKGROUND

The differential impact of serum lipids and their targets for lipid modification on cardiometabolic disease risk is debated. This study used Mendelian randomization to investigate the causal relationships and underlying mechanisms.

METHODS

Genetic variants related to lipid profiles and targets for lipid modification were sourced from the Global Lipids Genetics Consortium. Summary data for 10 cardiometabolic diseases were compiled from both discovery and replication data sets. Expression quantitative trait loci data from relevant tissues were employed to evaluate significant lipid-modifying drug targets. Comprehensive analyses including colocalization, mediation, and bioinformatics were conducted to validate the results and investigate potential mediators and mechanisms.

RESULTS

Significant causal associations were identified between lipids, lipid-modifying drug targets, and various cardiometabolic diseases. Notably, genetic enhancement of LPL (lipoprotein lipase) was linked to reduced risks of myocardial infarction (odds ratio [OR]1, 0.65 [95% CI, 0.57-0.75], P1=2.60×10-9; OR2, 0.59 [95% CI, 0.49-0.72], P2=1.52×10-7), ischemic heart disease (OR1, 0.968 [95% CI, 0.962-0.975], P1=5.50×10-23; OR2, 0.64 [95% CI, 0.55-0.73], P2=1.72×10-10), and coronary heart disease (OR1, 0.980 [95% CI, 0.975-0.985], P1=3.63×10-14; OR2, 0.64 [95% CI, 0.54-0.75], P2=6.62×10-8) across 2 data sets. Moreover, significant Mendelian randomization and strong colocalization associations for the expression of LPL in blood and subcutaneous adipose tissue were linked with myocardial infarction (OR, 0.918 [95% CI, 0.872-0.967], P=1.24×10-3; PP.H4, 0.99) and coronary heart disease (OR, 0.991 [95% CI, 0.983-0.999], P=0.041; PP.H4=0.92). Glucose levels and blood pressure were identified as mediators in the total effect of LPL on cardiometabolic outcomes.

CONCLUSIONS

The study substantiates the causal role of lipids in specific cardiometabolic diseases, highlighting LPL as a potent drug target. The effects of LPL are suggested to be influenced by changes in glucose and blood pressure, providing insights into its mechanism of action.

Association of gestational and childhood circulating C-peptide concentrations in the hyperglycemia and adverse pregnancy outcomes follow-up study

AIMS

This study examined the association of gravida C-peptide with progeny islet function and insulin sensitivity in the Hyperglycemia and Adverse Pregnancy Outcome Follow-up Study (HAPO FUS).

METHODS

Pregnancy 3rd trimester oral glucose tolerance test (OGTT), cord blood, and offspring OGTT glucose, C-peptide and insulin at age 10-14 years were analyzed for 4,121 mother-child dyads. Gravida fasting and 1-hour C-peptide concentration correlations with cord blood and childhood C-peptide, insulin, insulinogenic index and insulin sensitivity, and insulin resistance [HOMA-IR]), were assessed by multiple linear regression. Maternal covariates included age, gestational age, BMI and glucose at OGTT; child covariates included age, sex, pubertal stage, BMI z score and glucose.

RESULTS

Gravida fasting and 1-hour OGTT C-peptide was positively correlated with cord blood C-peptide, offspring OGTT C-peptide and insulin concentrations at fasting, 30 min, 1-hour and 2-hour at 10-14 years of age. Maternal fasting and 1-hour C-peptide concentrations were positively correlated with the insulinogenic index and HOMA-IR but inversely correlated with insulin sensitivity. Maternal C-peptide explained more variance than maternal glucose concentrations (3.0-17.9 % vs 0.2-3.5 %).

CONCLUSIONS/INTERPRETATION

The correlation between gravida and offspring C-peptide suggests that without crossing the placenta, insulin may influence the offspring pancreatic beta-cell development and insulin sensitivity.

Effect of smoking behaviour and related blood DNA methylation on visceral adipose tissues

BACKGROUND

Recent studies have found that tobacco smoking is associated with fat distribution, yet limited research has focused on its relationship with visceral adipose tissues (VATs). Furthermore, the cellular and molecular mechanisms underlying the interactions among smoking, epigenetic modifications, and VATs remain unknown.

METHOD

We performed univariable Mendelian randomization (MR) analysis to elucidate the causal relationship between smoking behaviours and VATs, including epicardial and pericardial adipose tissue (EPAT), liver fat (LF), and pancreas fat (PF). This approach could minimize the impact of confounders and reverse causality through utilizing genetic variants to proxy the smoking behaviours. Mediation MR analysis were conducted to detect potential mediators. Additionally, summary-data-based MR (SMR) and colocalization analysis were performed to explore the association between smoking-related DNA methylation and VATs.

RESULTS

We identified a convincing association between smoking initiation and increased EPAT (beta: 0.15, 95% CI: 0.06, 0.23, p = 7.01 × 10-4) and LF area (beta: 0.15, 95% CI = 0.05, 0.24, p = 2.85 × 10-3), respectively. Further mediation analysis suggested type 2 diabetes mellitus (T2DM) as a potential mediator within these co-relationships. When further exploring the associations between the smoking related DNA methylation and VATs, we identified that WT1 methylation at cg05222924 was significantly linked to a lower EPAT area (beta: -0.12, 95% CI: -0.16, -0.06, PFDR = 2.24 × 10-3), while GPX1 methylation at cg18642234 facilitated the deposition of EPAT (beta: 0.15, 95% CI: 0.10, 0.20, PFDR = 1.66 × 10-4).

CONCLUSION

Our study uncovered a significant causal effect between smoking and VATs, with T2DM identified as a potential mediator. Further investigation into DNA methylation yielded novel insights into the pathogenic role of smoking on EPAT.

Associations Between TCF7L2, PPARγ, and KCNJ11 Genotypes and Insulin Response to an Oral Glucose Tolerance Test: A Systematic Review

SCOPE

Insulin responses to standardized meals differ between individuals. This variability may in part be explained by genotype. This systematic review evaluates associations between genotype and insulin response to an oral glucose tolerance test (OGTT) in terms of insulin area under the curve (AUC).

METHODS AND RESULTS

Three electronic databases (Web of Science, Embase, PubMed) were searched for studies investigating associations between insulin AUC after an OGTT and single nucleotide polymorphisms (SNPs) belonging to the transcription factor 7 like 2 (TCF7L2) gene, the peroxisome proliferator-activated receptor gamma (PPARγ) gene, or the potassium inwardly rectifying channel subfamily J member 11 (KCNJ11) gene in persons without diabetes. A total of 5199 articles were identified, of which 38 were included. Among them were family-based studies (9), twin studies (2), and studies with unrelated participants (27). Seventeen articles investigated TCF7L2 (7 SNPs), 14 investigated PPARγ (1 SNP), and 8 investigated KCNJ11 (5 SNPs). For all investigated SNPs, at least half of the reports indicated no statistically significant association with postprandial insulin AUC.

CONCLUSION

No evidence was found for associations between TCF7L2, PPARγ, and KCNJ11 genotypes and insulin AUC after an OGTT. Future studies should investigate the effect of genetic risk scores on postprandial insulin.

Causal association between insulin sensitivity index and Alzheimer's disease

Evidence from observational and Mendelian randomization (MR) studies suggested that insulin resistance (IR) was associated with Alzheimer's disease (AD). However, the causal effects of different indicators of IR on AD remain inconsistent. Here, we aim to assess the causal association between the insulin sensitivity index (ISI), a measure of post-prandial IR, and the risk of AD. We first conducted primary and secondary univariable MR analyses. We selected 8 independent genome-wide significant (p < 5E-08, primary analyses) and 61 suggestive (p < 1E-05, secondary analyses) ISI genetic variants from large-scale genome-wide association studies (GWAS; N = 53 657), respectively, and extracted their corresponding GWAS summary statistics from AD GWAS, including IGAP2019 (N = 63 926) and FinnGen_G6_AD_WIDE (N = 412 181). We selected five univariable MR methods and used heterogeneity, horizontal pleiotropy test, and leave-one-out sensitivity analysis to confirm the stability of MR estimates. Finally, we conducted a meta-analysis to combine MR estimates from two non-overlapping AD GWAS datasets. We further performed multivariable MR (MVMR) to assess the potential mediating role of type 2 diabetes (T2D) on the association between ISI and AD using two MVMR methods. In univariable MR, utilizing 8 genetic variants in primary analyses, we found a significant causal association of genetically increased ISI with decreased risk of AD (OR = 0.79, 95% CI: 0.68-0.92, p = 0.003). Utilizing 61 genetic variants in secondary analyses, we found consistent findings of a causal effect of genetically increased ISI on the decreased risk of AD (OR = 0.89, 95% CI: 0.82-0.96, p = 0.003). Heterogeneity, horizontal pleiotropy test, and leave-one-out sensitivity analysis ensured the reliability of the MR estimates. In MVMR, we found no causal relationship between ISI and AD after adjusting for T2D (p > 0.05). We provide genetic evidence that increased ISI is significantly and causally associated with reduced risk of AD, which is mediated by T2D. These findings may inform prevention strategies directed toward IR-associated T2D and AD.

Association of organ iron levels with type 2 diabetes mellitus and glycemic traits: A bidirectional two-sample Mendelian randomization study

INTRODUCTION

Observational studies have found that higher iron levels are associated with an increased risk of diabetes mellitus. Given the limitations of causal inferences from observational studies and the expensive and time-consuming nature of randomized controlled trials, Mendelian randomization analysis presents a reasonable alternative to study causal relationships. Previous MR analyses studying iron levels and diabetes have used indirect markers of iron levels, such as serum ferritin, and found conflicting results. In this study, we performed bidirectional Mendelian Randomization analyses using organ iron (liver, spleen, and pancreas) levels, which are more direct markers of iron status, to study the causal association of iron levels with type 2 diabetes mellitus and glycaemic traits.

METHODS

Two sample MR analyses were employed bi-directionally to study the causal effect of liver, spleen, and pancreas iron levels on type 2 diabetes and glycaemic traits and the causal effect of type 2 diabetes on organ iron levels, using summary data from genome-wide association studies (UK-Biobank, DIAGRAM, and MAGIC consortia). SNPs associated with organ iron levels with a cut-off of P < 5 × 10-7 were used as instrumental variables for the MR analyses of the effect of organ iron levels on type 2 diabetes/glycaemic traits, and SNPs associated with diabetes mellitus with a cut-off of P < 5 × 10-8 were used as instrumental variables for the MR analyses of the causal effect of type 2 diabetes on organ iron levels. Serum ferritin (GWAS meta-analysis of deCODE, UK INTERVAL, and Denmark studies) and haemoglobin (Blood Cell consortium) were used as positive controls for the MR analysis with liver iron as the exposure. Primary analyses used the inverse variance weighted means of Wald's ratio. Sensitivity analyses included inverse variance weighted median, weighted mode, and MR-Egger methods.

RESULTS

Our findings reveal no causal association between liver and pancreas iron levels with type 2 diabetes (Liver iron: OR = 1.02, P = 0.1, Pancreas iron: OR = 1.11, P = 0.5). This also holds for glycaemic traits, except for the negative causal effect of liver iron levels on HbA1c (OR = 0.93, P = 0.001). Spleen iron levels had a negative causal effect on type 2 diabetes (OR = 0.94, P = 0.049). However, these exceptions are likely due to possible pleiotropy, as these associations can be explained by the effect of the genetic variants on factors that falsely decrease HbA1c levels. No causal association was found for the effect of type 2 diabetes on organ iron levels.

CONCLUSION

Organ iron levels, which are relatively more direct indicators of iron status, showed no causal association with type 2 diabetes in the European population.

Glucokinase Regulatory Protein as a Putative Target for Gestational Diabetes Mellitus and Related Complications: Evidence From the Mendelian Randomization Study

BACKGROUND

Gestational diabetes mellitus (GDM) is one of the most common complications of pregnancy and is highly associated with adverse perinatal outcomes and long-term health problems for the mother and offspring. However, there are respective limitations in the pharmacological strategies for the current treatment of GDM. Glucokinase regulatory protein (GCKR) has been associated with GDM in observational studies and animal experiments and thus represents a potential drug target of interest for investigation.

METHODS

We applied two-sample Mendelian randomization (MR) and colocalization analysis using summary-level data from genome-wide association studies of GCKR and GDM. Two-step MR was used to explore the mediating effects of several metabolic factors on the association. We also applied MR to explore the associations of GCKR levels with GDM-related outcomes. Finally, we performed a phenome-wide association study (PheWAS) to query the potential effects of altered GCKR levels across multiple health categories.

RESULTS

We found a significant association between elevated GCKR levels and GDM (OR = 3.466, 95% CI = 2.401-5.002, p = 3.16 × 10-11), also supported by the colocalization analysis ([Pcoloc] = 0.997). The estimates were replicated in an independent study (OR = 2.640, 95% CI = 1.983-3.513, p = 2.84 × 10-11, Pcoloc = 0.983). Elevated GCKR levels were also associated with higher risk of type 2 diabetes (OR = 2.183, 95% CI = 1.846-2.581, p = 6.53 × 10-20). Two-step MR suggested that fasting glucose, fasting insulin, and triglycerides partly mediated the causal relationship. PheWAS found that targeting GCKR may improve renal function and glucose homeostasis but cause dyslipidemia and uric acid abnormalities.

CONCLUSIONS

This study provided novel evidence that circulating GCKR levels are causally implicated in GDM and related complications, suggesting that it may be a promising target for treatment.

Systematic Mendelian Randomization Exploring Druggable Genes for Hemorrhagic Strokes

Patients with hemorrhagic stroke have high rates of morbidity and mortality, and drugs for prevention are very limited. Mendelian randomization (MR) analysis can increase the success rate of drug development by providing genetic evidence. Previous MR analyses only analyzed the role of individual drug target genes in hemorrhagic stroke; therefore, we used MR analysis to systematically explore the druggable genes for hemorrhagic stroke. We sequentially performed summary-data-based MR analysis and two-sample MR analysis to assess the associations of all genes within the database with intracranial aneurysm, intracerebral hemorrhage, and their subtypes. Validated genes were further analyzed by colocalization. Only genes that were positive in all three analyses and were druggable were considered desirable genes. We also explored the mediators of genes affecting hemorrhagic stroke incidence. Finally, the associations of druggable genes with other cardiovascular diseases were analyzed to assess potential side effects. We identified 56 genes that significantly affected hemorrhagic stroke incidence. Moreover, TNFSF12, SLC22A4, SPARC, KL, RELT, and ADORA3 were found to be druggable. The inhibition of TNFSF12, SLC22A4, and SPARC can reduce the risk of intracranial aneurysm, subarachnoid hemorrhage, and intracerebral hemorrhage. Gene-induced hypertension may be a potential mechanism by which these genes cause hemorrhagic stroke. We also found that blocking these genes may cause side effects, such as ischemic stroke and its subtypes. Our study revealed that six druggable genes were associated with hemorrhagic stroke, and the inhibition of TNFSF12, SLC22A4, and SPARC had preventive effects against hemorrhagic strokes.

The role of glucose-6-phosphatase activity in glucose homeostasis and its potential for diabetes therapy

Glucose-6-phosphatase catalytic subunit (G6PC)1 and G6PC2 are crucial for glucose metabolism, regulating processes like glycolysis, gluconeogenesis, and glycogenolysis. Despite their structural and functional similarities, G6PC1 and G6PC2 exhibit distinct tissue-specific expression patterns, G6P hydrolysis kinetics, and physiological functions. This review provides a comprehensive overview of their enzymology and distinct roles in glucose homeostasis. We examine how inactivating mutations in G6PC1 lead to glycogen storage disease, and how elevated G6PC1 and G6PC2 expression can affect the incidence of diabetic complications, risk for type 2 diabetes mellitus (T2DM) and various cancers. We also discuss the potential of inhibiting G6PC1 and G6PC2 to protect against complications from elevated blood glucose levels, and highlight drug development efforts targeting G6PC1 and G6PC2, and the therapeutic potential of inhibitors for disease prevention.

Epigenome-wide association study of objectively measured physical activity in peripheral blood leukocytes

BACKGROUND

Few studies have explored the association between DNA methylation and physical activity. The aim of this study was to evaluate the association of objectively measured hours of sedentary behavior (SB) and moderate physical activity (MPA) with DNA methylation. We further aimed to explore the association between SB or MPA related CpG sites and cardiometabolic traits, gene expression, and genetic variation.

RESULTS

For discovery, we performed cross sectional analyses in pregnant women from the Epigenetics in pregnancy (EPIPREG) sample with both DNA methylation (Illumina MethylationEPIC BeadChip) and objectively measured physical activity data (SenseWear™ Pro 3 armband) (European = 244, South Asian = 109). For EWAS of SB and MPA, two main models were designed: model (1) a linear mixed model adjusted for age, smoking, blood cell composition, including ancestry as random intercept, and model (2) which was additionally adjusted for the total number of steps per day. In model 1, we did not identify any CpG sites associated with neither SB nor MPA. In model 2, SB was positively associated (false discovery rate, FDR < 0.05) with two CpG sites within the VSX1 gene. Both CpG sites were positively associated with BMI and were associated with several genetic variants in cis. MPA was associated with 122 significant CpG sites at FDR < 0.05 (model 2). We further analyzed the ten most statistically significant MPA related CpG sites and found that they presented opposite associations with sedentary behavior and BMI. We were not able to replicate the SB and MPA-related CpG sites in the Avon Longitudinal Study of Parents and Children (ALSPAC). ALSPAC had available objectively measured physical activity data from Actigraph (without steps/day available) and leucocyte DNA methylation data collected during adolescence (n = 408, European).

CONCLUSION

This study suggests associations of objectively measured SB and MPA with maternal DNA methylation in peripheral blood leukocytes, that needs to be confirmed in larger samples of similar study design.

Genetic Links Between Metabolic Syndrome and Osteoarthritis: Insights From Cross-Trait Analysis

CONTEXT

Previous observational studies have indicated a bidirectional association between metabolic syndrome (MetS) and osteoarthritis (OA). However, it remains unclear whether these bidirectional associations reflect causal relationships or shared genetic factors, and the underlying biological mechanisms of this association are not fully understood.

OBJECTIVE

We aimed to explore the genetic connection between MetS and OA using genome-wide association study (GWAS) summary data.

METHODS

Leveraging summary statistics from GWAS conducted by the UK Biobank and the Glucose and Insulin-related Traits Consortium (MAGIC), we performed global genetic correlation analyses, genome-wide cross-trait meta-analyses, and a bidirectional two-sample Mendelian randomization analyses using summary statistics from GWAS to comprehensively assess the relationship of MetS and OA.

RESULTS

We first detected an extensive genetic correlation between MetS and OA (rg = 0.393, P = 1.52 × 10-18), which was consistent in 4 MetS components, including waist circumference, triglycerides, hypertension, and high-density lipoprotein cholesterol and OA with rg ranging from -0.229 to 0.490. We then discovered 32 variants jointly associated with MetS and OA through Multi-Trait Analysis of GWAS (MTAG). Co-localization analysis found 12 genes shared between MetS and OA, with functional implications in several biological pathways. Finally, Mendelian randomization analysis suggested genetic liability to MetS significantly increased the risk of OA, but no reverse causality was found.

CONCLUSION

Our results illustrate a common genetic architecture, pleiotropic loci, as well as causality between MetS and OA, potentially enhancing our knowledge of high comorbidity and genetic processes that overlap between the 2 disorders.

The MTNR1B Rs724030 variant is associated with islet function and women waist-to-hip ratio in healthy subjects

Objective

This study aims to investigate the associations between MTNR1B rs724030 A>G variant and prediabetes risk, along with their correlations with clinical features, including plasma glucose and serum insulin levels during oral glucose tolerance test (OGTT), islet function, insulin resistance, and plasma lipid levels. In particular, we investigated whether there are sex dimorphisms in the impact of this variant on islet function/insulin resistance.

Methods

We included 3415 glucose-tolerant healthy and 1744 prediabetes individuals based on OGTT. Binary logistic regression was performed to evaluate the relationships between rs724030 in MTNR1B and prediabetes under the additive model. Additionally, multiple linear regression was utilized to investigate the associations between this variant and glycemic-related quantitative traits and lipid levels.

Results

While no association was observed between the rs724030 variant in MTNR1B and prediabetes risk in the overall cohort (P > 0.05), we found the G allele of this variant was associated with higher fasting and 30-minute plasma glucose levels, decreased Insulinogenic Index (IGI), and oral disposition index (DIo) (P = 0.009, 0.001, 0.001, and 0.007, respectively) in the normal glucose tolerance (NGT) individuals with normal BMI levels. Furthermore, we also found significant associations between this variant and IGI, corrected insulin response (CIR), and DIo (All P < 0.001) in female individuals whose waist-to-hip ratio (WHR) is greater than 0.85, with considerable heterogeneity (Phet = 0.009, 0.030, and 0.049, respectively) to male participants in the NGT individuals, but not in the impaired fasting glucose (IFG)/impaired glucose tolerance (IGT) individuals. Additionally, no association was observed between this variant and insulin clearance (All P > 0.05).

Conclusions

The MTNR1B rs724030 variant contributes to glycemic traits and islet function, and its effects have sex dimorphisms in the NGT individuals after stratifying by WHR. All these findings provide a basis for accurately assessing islet function in healthy populations and offer a new perspective on precision prevention.

The impact of metabolic syndrome on hepatocellular carcinoma: a mendelian randomization study

Traditional epidemiological studies are susceptible to confounding factors. To clarify the impact of metabolic syndrome and its diagnostic components on hepatocellular carcinoma, we conducted a preliminary mendelian randomization analysis with metabolic syndrome and its diagnostic components as exposures and hepatocellular carcinoma as the outcome. Another set of genetic data related to hepatocellular carcinoma was used as a validation cohort, repeating the mendelian randomization analysis and combining the two groups for a meta-analysis. Preliminary analysis showed that metabolic syndrome (P-value = 0.002) and waist circumference (P-value = 0.026) are significantly positively correlated with an increased risk of hepatocellular carcinoma. After multiple testing corrections, metabolic syndrome (PFDR-value = 0.013) remained significant, although the association between waist circumference (PFDR-value = 0.079) and hepatocellular carcinoma was considered suggestive, the meta-analysis further confirmed the impact of metabolic syndrome (P-value = 0.0002) and waist circumference (P-value = 0.0038) in increasing the risk of hepatocellular carcinoma. After adjusting for the genetic predictive effects of all exposures, waist circumference was found to be a key factor significantly influencing the relationship between metabolic syndrome and hepatocellular carcinoma. In summary, our study indicates that metabolic syndrome increases the risk of hepatocellular carcinoma, particularly among individuals with a larger waist circumference.

Reduced circulating sphingolipids and CERS2 activity are linked to T2D risk and impaired insulin secretion

Gestational diabetes mellitus (GDM), a transient form of diabetes that resolves postpartum, is a major risk factor for type 2 diabetes (T2D) in women. While the progression from GDM to T2D is not fully understood, it involves both genetic and environmental components. By integrating clinical, metabolomic, and genome-wide association study (GWAS) data, we identified associations between decreased sphingolipid biosynthesis and future T2D, in part through the rs267738 allele of the CERS2 gene in Hispanic women shortly after a GDM pregnancy. To understand the impact of the CERS2 gene and risk allele on glucose regulation, we examined whole-body Cers2 knockout and rs267738 knock-in mice. Both models exhibited glucose intolerance and impaired insulin secretion in vivo. Islets isolated from these models also demonstrated reduced β cell function, as shown by decreased insulin secretion ex vivo. Overall, reduced circulating sphingolipids may indicate a high risk of GDM-to-T2D progression and reflect deficits in CERS2 activity that negatively affect glucose homeostasis and β cell function.

Exploring the Role of Glycine Metabolism in Coronary Artery Disease: Insights from Human Genetics and Mouse Models

Background: Circulating glycine levels have been associated with reduced risk of coronary artery disease (CAD) in humans but these associations have not been observed in all studies. We evaluated whether the relationship between glycine levels and atherosclerosis was causal using genetic analyses in humans and feeding studies in mice. Methods: Serum glycine levels were evaluated for association with risk of CAD in the UK Biobank. Genetic determinants of glycine levels were identified through a genome-wide association study (GWAS) and used to evaluate the causal relationship between glycine and risk of CAD by Mendelian randomization (MR). A dietary supplementation study was carried out with atherosclerosis-prone apolipoprotein E deficient (ApoE-/-) mice to determine the effects of increased circulating glycine levels on cardiometabolic traits and aortic lesion formation. Results: Among 105,718 UK Biobank subjects, elevated serum glycine levels were associated with significantly reduced risk of prevalent CAD (Quintile 5 vs. Quintile 1 OR = 0.76, 95% CI 0.67-0.87; p < 0.0001) and incident CAD (Quintile 5 vs. Quintile 1 HR = 0.70, 95% CI 0.65-0.77; p < 0.0001) after adjustment for age, sex, ethnicity, anti-hypertensive and lipid-lowering medications, blood pressure, kidney function, and diabetes. A GWAS meta-analysis with 230,947 subjects identified 61 loci for glycine levels, of which 26 were novel. MR analyses provided modest evidence that genetically elevated glycine levels were causally associated with reduced systolic blood pressure and risk of type 2 diabetes, but did not provide significant evidence for an association with decreased risk of CAD. Glycine supplementation in mice had no effects on cardiometabolic traits or atherosclerotic lesion development. Conclusions: While expanding the genetic architecture of glycine metabolism, MR analyses and in vivo feeding studies did not provide evidence that the clinical association of this amino acid with atherosclerosis represents a causal relationship.

Mediators of the association between nut consumption and cardiovascular diseases: a two-step mendelian randomization study

Previous observational studies have reported inconsistent associations between nut consumption and cardiovascular diseases (CVD). This study aims to identify the causal relationship between different types of nuts consumption and CVD, and to quantify the potential mediating effects of cardiometabolic factors. We utilized Genome-Wide Association Study (GWAS) data to assess the causal effects of nut consumption on CVD using two-sample Mendelian randomization (MR) and a two-step MR analysis. The inverse variance weighted (IVW) method indicated that processed (salted or roasted) peanuts were potentially and positively associated with ischaemic heart disease (IHD) (OR 1.4866; 95%CI 1.0491-2.1065). No causal relationships were found between nuts consumption and other CVD outcomes, including atrial fibrillation, angina, coronary atherosclerosis, coronary heart disease, IHD, myocardial infarction, subarachnoid hemorrhage, intracerebral haemorrhage and stroke. Both MR-Egger and median-based methods yielded similar results to IVW. Furthermore, in the two-step MR analysis, fasting insulin, low-density lipoprotein cholesterol and fasting blood glucose were identified as mediators in the potential causal relationship between processed peanuts and IHD, explaining 16.98%, 6.38% and 4.91% of the mediation, respectively. In total, these mediators accounted for 28.27% of the association between salted or roasted peanuts and IHD.

Evaluating the Causal Effect of Circulating Proteome on Glycemic Traits: Evidence From Mendelian Randomization

Exploring the mechanisms underlying abnormal glycemic traits is important for deciphering type 2 diabetes and characterizing novel drug targets. This study aimed to decipher the causal associations of circulating proteins with fasting glucose (FG), 2-h glucose after an oral glucose challenge (2hGlu), fasting insulin (FI), and glycated hemoglobin (HbA1c) using large-scale proteome-wide Mendelian randomization (MR) analyses. Genetic data on plasma proteomes were obtained from 10 proteomic genome-wide association studies. Both cis-protein quantitative trait loci (pQTLs) and cis + trans-pQTLs MR analyses were conducted. Bayesian colocalization, Steiger filtering analysis, assessment of protein-altering variants, and mapping expression QTLs to pQTLs were performed to investigate the reliability of the MR findings. Protein-protein interaction, pathway enrichment analysis, and evaluation of drug targets were performed. Thirty-three proteins were identified with causal effects on FG, FI, or HbA1c but not 2hGlu in the cis-pQTL analysis, and 93 proteins had causal effects on glycemic traits in the cis + trans-pQTLs analysis. Most proteins were either considered druggable or drug targets. In conclusion, many novel circulating protein biomarkers were identified to be causally associated with glycemic traits. These biomarkers enhance the understanding of molecular etiology and provide insights into the screening, monitoring, and treatment of diabetes.

ARTICLE HIGHLIGHTS

Associations between Type 2 Diabetes Mellitus, Metabolic Traits, and Abdominal Aortic Aneurysm: A Cross-Ethnic Mendelian Randomization Analysis

BACKGROUND

Evidence suggests that type 2 diabetes mellitus (T2DM) may protect from abdominal aortic aneurysm (AAA). However, it is unclear whether a causal relationship exists between these 2 conditions and, if so, whether it remains consistent among racial groups.

METHODS

Cross-ethnic Mendelian randomization (MR) was used to examine the causal relationships between T2DM, metabolic traits, and AAA. Inverse variance weighted (IVW) was the primary analysis tool, supplemented by MR-Egger, weighted median, and MR Pleiotropy RESidual Sum and Outlier. Heterogeneity and horizontal pleiotropy were assessed using the Cochran's Q test and MR-Egger intercept, respectively.

RESULTS

According to IVW, an inverse correlation between T2DM and AAA was detected in Europeans (odds ratio [OR] 0.91, 95% confidence interval [CI] 0.84-0.99; P = 0.034) and East Asians (OR 0.87, 95% CI 0.77-0.99; P = 0.038). Fasting glucose was inversely associated with AAA in Europeans (OR 0.56, 95% CI 0.33-0.96; P = 0.034) but not in East Asians. In Europeans, fasting insulin was a risk factor for AAA (OR 3.03, 95% CI 1.53-6.01; P = 0.001), while 2-hour glucose was protective (OR 0.67, 95% CI 0.49-0.91; P = 0.011). Glycated hemoglobin (HbA1c) had no effect. Insufficient instrumental variables prevented the evaluation of the relationships of fasting insulin, HbA1c, and 2-hour glucose with AAA in East Asians.

CONCLUSIONS

T2DM protects against AAA in Europeans and East Asians. The effects of different glucose metabolism characteristics on AAA may inform AAA treatment.

Adipose tissue eQTL meta-analysis highlights the contribution of allelic heterogeneity to gene expression regulation and cardiometabolic traits

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. Compared with primary eQTL signals, nonprimary eQTL signals had lower effect sizes, lower minor allele frequencies and less promoter enrichment; they corresponded to genes with higher heritability and higher tolerance for loss of function. Colocalization of eQTLs with genome-wide association study (GWAS) signals for 28 cardiometabolic traits identified 1,835 genes. Inclusion of nonprimary eQTL signals increased discovery of colocalized GWAS-eQTL signals by 46%. Furthermore, 21 genes with ≥2 colocalized GWAS-eQTL signals showed a mediating gene dosage effect on the GWAS trait. Thus, expanded eQTL identification reveals more mechanisms underlying complex traits and improves understanding of the complexity of gene expression regulation.

Exploring the causal relationship between asthma in the metabolic syndrome: a Mendelian randomization study

BACKGROUND

Previous observational studies have indicated a potential association between metabolic syndrome (MetS) and asthma, though the causal nature of this connection is still uncertain. Our study used Mendelian randomization (MR) to examine the causal relationship between metabolic syndrome (MetS) and its components with asthma.

METHODS

This study utilized single nucleotide polymorphisms (SNPs) related to MetS and its components, sourced from publicly available genome-wide association studies (GWAS) data, in combination with asthma data from the FinnGen database. Statistical analyses were conducted using the inverse variance weighted method (IVW), MR-Egger, and weighted median method. The robustness of the findings was confirmed through various sensitivity analyses.

RESULTS

The IVW analysis indicated that MetS was associated with an increased risk of asthma (OR = 1.0781, 95% CI = 1.0255-1.1333, p = 0.0032). Among the components of MetS, waist circumference (WC) showed a strong association with asthma (OR = 1.4777, 95% CI = 1.3412-1.6281, p = 2.8707 × 10-15). Conversely, high-density lipoprotein cholesterol (HDL-C) was found to be inversely related to the risk of asthma (OR = 0.9186, 95% CI = 0.8669-0.9734, p = 0.0041).

CONCLUSION

The findings of this study support that MetS and its specific components, particularly abdominal obesity, are linked to a higher risk of asthma, while HDL-C might offer protective effects against asthma. These findings provide a foundation both for further research and possible therapeutic interventions.

Shared genetic architecture and bidirectional clinical risks within the psycho-metabolic nexus

BACKGROUND

Increasing evidence suggests a complex interplay between psychiatric disorders and metabolic dysregulations. However, most research has been limited to specific disorder pairs, leaving a significant gap in our understanding of the broader psycho-metabolic nexus.

METHODS

This study leveraged large-scale cohort data and genome-wide association study (GWAS) summary statistics, covering 8 common psychiatric disorders and 43 metabolic traits. We introduced a comprehensive analytical strategy to identify shared genetic bases sequentially, from key genetic correlation regions to local pleiotropy and pleiotropic genes. Finally, we developed polygenic risk score (PRS) models to translate these findings into clinical applications.

FINDINGS

We identified significant bidirectional clinical risks between psychiatric disorders and metabolic dysregulations among 310,848 participants from the UK Biobank. Genetic correlation analysis confirmed 104 robust trait pairs, revealing 1088 key genomic regions, including critical hotspots such as chr3: 47588462-50387742. Cross-trait meta-analysis uncovered 388 pleiotropic single nucleotide variants (SNVs) and 126 shared causal variants. Among variants, 45 novel SNVs were associated with psychiatric disorders and 75 novel SNVs were associated with metabolic traits, shedding light on new targets to unravel the mechanism of comorbidity. Notably, RBM6, a gene involved in alternative splicing and cellular stress response regulation, emerged as a key pleiotropic gene. When psychiatric and metabolic genetic information were integrated, PRS models demonstrated enhanced predictive power.

INTERPRETATION

The study highlights the intertwined genetic and clinical relationships between psychiatric disorders and metabolic dysregulations, emphasising the need for integrated approaches in diagnosis and treatment.

FUNDING

The National Key Research and Development Program of China (2023YFC2506200, SHH). The National Natural Science Foundation of China (82273741, SY).

Effects of Genetic Risk on Incident Type 2 Diabetes and Glycemia: The T2D-GENE Lifestyle Intervention Trial

CONTEXT

Lifestyle intervention prevents or delays type 2 diabetes (T2D) in subjects at a high risk of T2D. However, it is not known whether genetic variants modify the effect on incident T2D during lifestyle intervention.

OBJECTIVE

To investigate whether a low or high genetic risk has effects on incident T2D in a group-based lifestyle intervention study.

METHODS

The T2D-GENE trial involved 973 men from the Metabolic Syndrome in Men (METSIM) cohort, aged 50-75 years, body mass index ≥25 kg/m2, fasting plasma glucose 5.6-6.9 mmol/L, hemoglobin A1c < 48 mmol/mol, and either a low or high genetic risk score for T2D. There were 2 intervention groups, a low (n = 315) and high genetic risk for T2D (n = 313). They were provided with a 3-year group-based intervention with access to a web portal focused on healthy diet and physical activity. There were also corresponding population-based control groups at low (n = 196) and high (n = 149) genetic risk for T2D who had two laboratory visits (0 and 3 years) and general health advice as a part of their METSIM cohort protocol. The primary outcome was incident T2D, and a secondary outcome was glycemia.

RESULTS

The intervention significantly lowered the risk of T2D among the participants with a high genetic risk for T2D [hazards ratio (HR) 0.30, 95% confidence interval (CI) 0.16-0.56, P < .001) whereas in the low genetic risk group the effect was not significant (HR 0.69, 95% CI 0.36-1.32, P = .262). The intervention effect was not significantly different between the high and low genetic risk groups (P = .135). The intervention significantly ameliorated the worsening of glycemia and decreased weight both in the low and high genetic risk groups.

CONCLUSION

Our results showed that individuals with a high genetic risk for T2D benefitted from a low-cost group-based intervention focusing on healthy diet and physical activity. Therefore, all individuals at risk of T2D should be encouraged to make lifestyle changes regardless of genetic risk.

Population-scale skeletal muscle single-nucleus multi-omic profiling reveals extensive context specific genetic regulation

Skeletal muscle, the largest human organ by weight, is relevant in several polygenic metabolic traits and diseases including type 2 diabetes (T2D). Identifying genetic mechanisms underlying these traits requires pinpointing cell types, regulatory elements, target genes, and causal variants. Here, we use genetic multiplexing to generate population-scale single nucleus (sn) chromatin accessibility (snATAC-seq) and transcriptome (snRNA-seq) maps across 287 frozen human skeletal muscle biopsies representing nearly half a million nuclei. We identify 13 cell types and integrate genetic variation to discover >7,000 expression quantitative trait loci (eQTL) and >100,000 chromatin accessibility QTLs (caQTL) across cell types. Learning patterns of e/caQTL sharing across cell types increased precision of effect estimates. We identify high-resolution cell-states and context-specific e/caQTL with significant genotype by context interaction. We identify nearly 2,000 eGenes colocalized with caQTL and construct causal directional maps for chromatin accessibility and gene expression. Almost 3,500 genome-wide association study (GWAS) signals across 38 relevant traits colocalize with sn-e/caQTL, most in a cell-specific manner. These signals typically colocalize with caQTL and not eQTL, highlighting the importance of population-scale chromatin profiling for GWAS functional studies. Finally, our GWAS-caQTL colocalization data reveal distinct cell-specific regulatory paradigms. Our results illuminate the genetic regulatory architecture of human skeletal muscle at high resolution epigenomic, transcriptomic, and cell-state scales and serve as a template for population-scale multi-omic mapping in complex tissues and traits.

Associations of Combined Genetic and Lifestyle Risks with Incident Type 2 Diabetes in the UK Biobank

Background

Type 2 diabetes (T2D) results from a complex interplay between genetic predisposition and lifestyle factors. Both genetic susceptibility and unhealthy lifestyle are known to be associated with elevated T2D risk. However, their combined effects on T2D risk are not well studied. We aimed to determine whether unhealthy modifiable health behaviors were associated with similar increases in the risk of incident T2D among individuals with different levels of genetic risk.

Methods

We performed a genetic risk score (GRS) by lifestyle interaction analysis within 332,251 non-diabetic individuals at baseline from the UK Biobank. Multi-ancestry GRS were calculated by summing the effects of 783 T2D-associated variants and ranked into tertiles. We used baseline self-reported data on smoking, BMI, physical activity level, and diet quality to categorize participants as having a healthy, intermediate, or unhealthy lifestyle. Cox proportional hazards regression models were used to generate adjusted hazards ratios (HR) of T2D risk and associated 95% confidence intervals (CI).

Results

During follow-up (median 13.6 years), 13,128 (4.0%) participants developed T2D. GRS (P < 0.001) and lifestyle classification (P < 0.001) were independently associated with increased risk for T2D. Compared with healthy lifestyle, unhealthy lifestyle was associated with increased T2D risk in all genetic risk strata, with adjusted HR ranging from 7.11 (low genetic risk) to 16.33 (high genetic risk).

Conclusions

High genetic risk and unhealthy lifestyle were the most significant contributors to the development of T2D. Individuals at all levels of genetic risk can greatly mitigate their risk for T2D through lifestyle modifications.

Environmental contaminants, sex hormones and SHBG in an elderly population

INTRODUCTION

Effects of environmental contaminants (ECs) on endocrine systems have been reported, but few studies assessed associations between ECs and sex hormones (SH) in elderly. Aim of this study was to investigate whether blood concentrations of four classes of ECs were associated with SH concentrations in elderly.

METHODS

Samples from participants of the cross-sectional population-based Prospective Investigation of the Vasculature in Uppsala Seniors study (PIVUS, 70-year-old men and women, n = 1016) were analyzed using validated mass spectrometry-based methods for SH (testosterone (T), dihydrotestosterone (DHT), estrone and estradiol (E2)); 23 persistent organic pollutants (POPs); 8 perfluoroalkyl substances (PFAS); 4 phthalates and 11 metals. SH binding globulin (SHBG) was analyzed using immunoassay. The measured concentrations were normalized, and the values converted to a z-scale. Linear regression analyses were conducted to assess association between concentration of the SH, SHBG and E2/T (aromatase enzyme index, AEI) with the ECs. Multiple linear regression analyses were performed to model the relationships.

RESULTS

The strongest associations were observed with the polychlorinated biphenyls (PCBs). In men, the strongest associations with concentrations of SH and SHBG were seen for PCBs containing >5 chlorine, monoethyl phthalate (MEP), Ni and Cd; and in women, with PCBs, MEP, several of the PFAS, Cd, Co, and Ni. Difference in the effect of ECs on AEI between men and women were observed. Area under the ROC curve for the models predicting abnormal values of SH and SHBG >0.75 due to the effects of ECs was observed for T, DHT, and E2 in men, and for E2 and SHBG in women.

CONCLUSIONS

Results of this study suggest that in elderly subjects, concentrations of many ECs associated with concentrations of SH and SHBG, and AEI. Further studies are needed to confirm the findings and to assess effect of the pollutants on endocrine system function in elderly.

Personalized phosphoproteomics of skeletal muscle insulin resistance and exercise links MINDY1 to insulin action

Type 2 diabetes is preceded by a defective insulin response, yet our knowledge of the precise mechanisms is incomplete. Here, we investigate how insulin resistance alters skeletal muscle signaling and how exercise partially counteracts this effect. We measured parallel phenotypes and phosphoproteomes of insulin-resistant (IR) and insulin-sensitive (IS) men as they responded to exercise and insulin (n = 19, 114 biopsies), quantifying over 12,000 phosphopeptides in each biopsy. Insulin resistance involves selective and time-dependent alterations to signaling, including reduced insulin-stimulated mTORC1 and non-canonical signaling responses. Prior exercise promotes insulin sensitivity even in IR individuals by "priming" a portion of insulin signaling prior to insulin infusion. This includes MINDY1 S441, which we show is an AKT substrate. We found that MINDY1 knockdown enhances insulin-stimulated glucose uptake in rat myotubes. This work delineates the signaling alterations in IR skeletal muscle and identifies MINDY1 as a regulator of insulin action.

Insulin-related traits and prostate cancer: A Mendelian randomization study

Investigating the causal relationship between insulin secretion and prostate cancer (PCa) development is challenging due to the multifactorial nature of PCa, which complicates the isolation of the specific impact of insulin-related factors. We conducted a Mendelian randomization (MR) study to investigate the associations between insulin secretion-related traits and PCa. We used 36, 60, 56, 23, 48, and 49 single nucleotide polymorphisms (SNPs) as instrumental variables for fasting insulin, insulin sensitivity, proinsulin, and proinsulin in nondiabetic individuals, individuals with diabetes, and individuals receiving exogenous insulin, respectively. These SNPs were selected from various genome-wide association studies. To clarify the causal relationship between insulin-related traits and PCa, we utilized a multivariable MR analysis to adjust for obesity and body fat percentage. Additionally, two-step Mendelian randomization was conducted to assess the role of insulin-like growth factor 1 (IGF-1) in the relationship between proinsulin and PCa. Two-sample MR analysis revealed strong associations between genetically predicted fasting insulin, insulin sensitivity, proinsulin, and proinsulin in nondiabetic individuals and the development of PCa. After adjustment for obesity and body fat percentage using multivariable MR analysis, proinsulin remained significantly associated with PCa, whereas other factors were not. Furthermore, two-step MR analysis demonstrated that proinsulin acts as a negative factor in prostate carcinogenesis, largely independent of IGF-1. This study provides evidence suggesting that proinsulin may act as a negative factor contributing to the development of PCa. Novel therapies targeting proinsulin may have potential benefits for PCa patients, potentially reducing the need for unnecessary surgical treatments.

Association between walking pace and heart failure: A Mendelian randomization analysis

BACKGROUND AND AIM

The relationship between walking pace and heart failure (HF) has been recognized, yet the directionality and underlying mediating risk factors remain unclear.

METHODS AND RESULTS

This study utilized bidirectional two-sample Mendelian randomization (MR) with genome-wide association studies (GWAS) summary statistics to assess the causal relationships between walking pace and HF. Additionally, we employed a two-step Multivariable Mendelian Randomization (MVMR) to explore potential mediating factors. We further validated our findings by conducting two-sample MR with another available GWAS summary data on heart failure. Results indicated that genetically predicted increases in walking pace were associated with a reduced risk of HF (odds ratio (OR), 0.589, 95% confidence interval (CI): 0.417-0.832). Among the considered mediators, the waist-to-hip ratio (WHR) accounts for the largest proportion of the effect (45.7%, 95% CI: 13.2%, 78.2%). This is followed by type 2 diabetes at 24.4% (95% CI: 6.7%, 42.0%) and triglycerides at 18.6% (95% CI: 4.5%, 32.7%). Furthermore, our findings reveal that genetically predicted HF risk (OR, 0.975, 95% CI: 0.960-0.991) is associated with a slower walking pace. Validated findings were consistent with the main results.

CONCLUSIONS

In conclusion, MR analysis demonstrates that a slow walking pace is a reliable indicator of an elevated risk of HF, and the causal relationship is bidirectional. Interventions focusing on waist-to-hip ratio, type 2 diabetes, and triglycerides may provide valuable strategies for HF prevention in individuals with a slow walking pace.

Genetics of glucose homeostasis in pregnancy and postpartum

AIMS/HYPOTHESIS

Pregnancy is accompanied by maternal metabolic adaptations to ensure fetal growth and development, including insulin resistance, which occurs primarily during the second and third trimesters of pregnancy, and a decrease in fasting blood sugar levels over the course of pregnancy. Glucose-related traits are regulated by genetic and environmental factors and modulated by physiological variations throughout the life course. We addressed the hypothesis that there are both overlaps and differences between genetic variants associated with glycaemia-related traits during and outside of pregnancy.

METHODS

Genome-wide SNP data were used to identify genetic variations associated with glycaemia-related traits measured during an OGTT performed at ~28 weeks' gestation in 8067 participants in the Hyperglycaemia and Adverse Pregnancy Outcome (HAPO) Study. Associations outside of pregnancy were determined in 3977 individuals who also participated in the HAPO Follow-Up Study at 11-14 years postpartum. A Bayesian classification algorithm was used to determine whether SNPs associated with fasting and 2 h glucose and fasting C-peptide during pregnancy had a pregnancy-predominant effect vs a similar effect during pregnancy and postpartum.

RESULTS

SNPs in six loci (GCKR, G6PC2, GCK, PPP1R3B, PCSK1 and MTNR1B) were significantly associated with fasting glucose during pregnancy, while SNPs in CDKAL1 and MTNR1B were associated with 1 h glucose and SNPs in MTNR1B and HKDC1 were associated with 2 h glucose. Variants in CDKAL1 and MTNR1B were associated with insulin secretion during pregnancy. Variants in multiple loci were associated with fasting C-peptide during pregnancy, including GCKR, IQSEC1, PPP1R3B, IGF1 and BACE2. GCKR and BACE2 were associated with 1 h C-peptide and GCKR, IQSEC1 and BACE2 with insulin sensitivity during pregnancy. The associations of MTNR1B with 2 h glucose, BACE2 with fasting and 1 h C-peptide and insulin sensitivity, and IQSEC1 with fasting C-peptide and insulin sensitivity that we identified during pregnancy have not been previously reported in non-pregnancy cohorts. The Bayesian classification algorithm demonstrated that the magnitude of effect of the lead SNP was greater during pregnancy compared with 11-14 years postpartum in PCSK1 and PPP1R3B with fasting glucose, in three loci, including MTNR1B, with 2 h glucose, and in six loci, including IGF1, with fasting C-peptide.

CONCLUSIONS/INTERPRETATION

Our findings support the hypothesis that there are both overlaps and differences between the genetic architecture of glycaemia-related traits during and outside of pregnancy. Genetic variants at several loci, including PCSK1, PPP1R3B, MTNR1B and IGF1, appear to influence glycaemic regulation in a unique fashion during pregnancy. Future studies in larger cohorts will be needed to replicate the present findings, fully characterise the genetics of maternal glycaemia during pregnancy and determine similarities to and differences from the non-gravid state.

Styrene and ethylbenzene exposure and type 2 diabetes mellitus: A longitudinal gene-environment interaction study

Styrene and ethylbenzene (S/EB) are identified as hazardous air contaminants that raise significant concerns. The association between S/EB exposure and the incidence of type 2 diabetes mellitus (T2DM), and the interaction between genes and environment, remains poorly understood. Our study consisted of 2219 Chinese adults who were part of the Wuhan-Zhuhai cohort. A follow-up assessment was conducted after six years. Exposure to S/EB was quantified by determining the concentrations of urinary biomarkers of exposure to S/EB (UBE-S/EB; urinary phenylglyoxylic acid level plus urinary mandelic acid level). Logistic regression models were constructed to investigate the relations of UBE-S/EB and genetic risk score (GRS) with T2DM prevalence and incidence. The interaction effects of UBE-S/EB and GRS on T2DM were investigated on multiplicative and additive scales. UBE-S/EB was dose-dependently and positively related to T2DM prevalence and incidence. Participants with high levels of UBE-S/EB [relative risk (RR) = 1.930, 95% confidence interval (CI): 1.157-3.309] or GRS (1.943, 1.110-3.462) demonstrated the highest risk of incident T2DM, in comparison to those with low levels of UBE-S/EB or GRS. Significant additive interaction between UBE-S/EB and GRS on T2DM incidence was discovered with relative excess risk due to interaction (95% CI) of 0.178 (0.065-0.292). The RR (95% CI) of T2DM incidence was 2.602 (1.238-6.140) for individuals with high UBE-S/EB and high GRS, compared to those with low UBE-S/EB and low GRS. This study presented the initial evidence that S/EB exposure was significantly related to increased risk of T2DM incidence, and the relationship was interactively aggravated by genetic predisposition.

Genetic proxies for therapy of insulin drug targets and risk of osteoarthritis: a drug-target Mendelian randomization analysis

BACKGROUND

The potential effects of insulin therapy on osteoarthritis (OA) risk are poorly understood. This study aimed to explore the causal relationship between insulin therapy and OA.

METHODS

Mendelian randomization (MR) analysis was performed to examine the association between genetically proxied inhibition of insulin targets and the risk of overall, hip (HOA) and knee OA (KOA). We then performed univariable MR using summary statistics regarding insulin target genes derived from the DrugBank database. Data related to blood glucose reduction levels were used as a proxy for insulin levels. Two phenotypes, type 2 diabetes, and glycosylated hemoglobin levels, were selected as positive controls to confirm the direction and validity of the proxies. The OA datasets were derived from the UK Biobank cohort. Multivariable MR was adjusted for body mass index, sedentary behavior, cigarette smoking, frequency of alcohol intake, age, and genetic sex.

RESULTS

Genetically proxied insulin therapy was associated with an increased risk of overall OA [odds ratio (OR):1.2595; 95% confidence interval (CI):1.0810-1.4675] and HOA (OR:1.4218; 95%CI:1.1240-1.7985), which remained consistent across multiple MR methods. After adjusting for confounders, we found evidence supporting a significant causal link with a higher risk of overall OA and HOA. A further two-step MR analysis revealed no significant mediation effects from the six mediators in the associations.

CONCLUSION

There was a causal association between genetically proxied insulin therapy and a higher risk of OA, especially HOA.

The association between metabolic syndrome and lung cancer risk: a Mendelian randomization study

Metabolic syndrome (MetS) is closely linked to cancer development, with emerging evidence suggesting its association with pulmonary carcinoma. However, causal relationships remain unclear due to observational study limitations. Employing Mendelian randomization, we investigated the causal link between MetS and lung cancer (LC) susceptibility. The data utilized in this study were obtained from the publicly available genetic variation summary database. The causal relationship was assessed using the inverse variance weighting method (IVW), weighted median method, and MR-Egger regression. A sensitivity analysis was carried out to confirm the robustness of the findings. Furthermore, risk factor analyses were conducted to explore potential mediators. Utilizing various analyses, MetS demonstrated a significant positive association with LC (OR, 1.22; 95% CI, 1.09-1.37, p = 7.57 × 10- 4), lung squamous cell carcinoma (LUSC) (OR, 1.47; 95%, 1.23-1.75, p = 2.22 × 10- 5), and small cell lung cancer (SCLC) (OR, 1.76; 95% CI, 1.37-2.26, p = 8.20 × 10- 6) but not lung adenocarcinoma (LUAD) (OR, 1.08; 95% CI, 0.94-1.24, p = 0.28). Risk factor analyses indicated that smoking, alcohol, body mass index, education, and type 2 diabetes might mediate the association. This study genetically validates and reinforces the evidence of MetS increasing the incidence of LC, including both LUSC) and SCLC, especially among individuals with abdominal obesity. It provides valuable insights for the development of lung cancer prevention strategies and directions for future research.

Impact of diabetes mellitus on the risk of Alzheimer's disease: a mendelian randomization study

BACKGROUND

The impact of diabetes on the risk of Alzheimer's disease remains uncertain. This study aimed to explore this issue from multiple perspectives by using the Mendelian randomization (MR) approach.

METHODS

Instrumental variables for predicting six diabetic traits (including insulin and blood glucose), eight metabolic risk factors for diabetes (including total cholesterol and blood pressure), and seven diabetic genes were extracted from their summary data. These data were derived from multiple European cohorts and included 31,684 to 810,865 subjects respectively. The two-sample MR, multivariate MR, and summary-data-based Mendelian randomization (SMR) methods were employed to determine the associations of these traits or genes with the risk of Alzheimer's disease.

RESULTS

The two-sample MR showed that elevated fasting insulin and total cholesterol levels were associated with an increased risk of dementia in Alzheimer's disease (P = 0.022, P = 0.041). Elevated systolic and diastolic blood pressure levels were associated with a decreased risk of dementia in Alzheimer's disease (P = 0.036, P = 0.025). The multivariate MR reported that adjusting for telomere length (a well-established biomarker of aging) did not change these findings (P < 0.05). Additionally, the two-sample MR showed that type 1 and type 2 diabetes did not affect the risk of Alzheimer's disease. The SMR also indicated that the diabetic genes did not affect the risk of this disease.

CONCLUSION

Multiple MR approaches concluded that fasting insulin, total cholesterol, and blood pressure, rather than diabetes, were potential metabolic variables that had an impact on the risk of Alzheimer's disease. However, aging might not be involved in these correlations.

Is there a genetic relationship between blood glucose and osteoarthritis? A mendelian randomization study

OBJECTIVE

The relationship between blood glucose levels and osteoarthritis (OA) is unclear. This study aimed to investigate the genetic causal relationship between blood glucose-related traits and OA.

METHODS

We first performed univariate Mendelian randomization (UVMR) analyses using published genome-wide association study (GWAS) datasets with fasting glucose (FG), 2 h-glucose post-challenge glucose (2hGlu), and glycosylated hemoglobin (HbA1c) as exposures, and hip osteoarthritis (HOA) and knee osteoarthritis (KOA) as outcomes; then, we performed inverse analyses of them. We used Inverse-variance weighted (IVW) analysis as the primary analysis, and sensitivity analyses were performed. Moreover, we performed multivariate Mendelian randomization (MVMR) to estimate the independent effect of exposure on outcome after adjusting for body mass index (BMI). Summarized data for blood glucose-related traits were obtained from the MAGIC Consortium study of the glucose trait genome and for OA from the UK Biobank and arcOGEN. Summarized data for BMI were obtained from the GIANT Consortium meta-analysis of individuals of European ancestry. A two-sided p value < 0.05 in UVMR was considered suggestive of significance when p < 0.0167 (Bonferroni correction p = 0.05/3 exposures) was considered statistically significant.

RESULTS

We found significant negative genetic causality of FG for HOA and KOA, and these associations remained significant after we adjusted for the effect of BMI [odds ratios (ORs) of 0.829 (0.687-0.999, p = 0.049) and 0.741 (0.570-0.964, p = 0.025)]. HbA1c also had an independent negative genetic causal effect on HOA after adjustment for BMI [0.665 (0.463-0.954, p = 0.027)]. At the same time, there was no evidence of reverse genetic causality of OA on blood glucose-related traits.

CONCLUSION

We further elucidated the relationship between blood glucose-related traits and OA by adjusting for the effect of BMI from a genetic causal perspective. This study provides new insights to further clarify the relationship between blood glucose levels and OA, as well as the pathogenesis, etiology and genetics of OA.

Effect of genetically predicted sclerostin on cardiovascular biomarkers, risk factors, and disease outcomes

Sclerostin inhibitors protect against osteoporotic fractures, but their cardiovascular safety remains unclear. We conducted a cis-Mendelian randomisation analysis to estimate the causal effect of sclerostin levels on cardiovascular risk factors. We meta-analysed three GWAS of sclerostin levels including 49,568 Europeans and selected 2 SNPs to be used as instruments. We included heel bone mineral density and hip fracture risk as positive control outcomes. Public GWAS and UK Biobank patient-level data were used for the study outcomes, which include cardiovascular events, risk factors, and biomarkers. Lower sclerostin levels were associated with higher bone mineral density and 85% reduction in hip fracture risk. However, genetically predicted lower sclerostin levels led to 25-85% excess coronary artery disease risk, 40% to 60% increased risk of type 2 diabetes, and worse cardiovascular biomarkers values, including higher triglycerides, and decreased HDL cholesterol levels. Results also suggest a potential (but borderline) association with increased risk of myocardial infarction. Our study provides genetic evidence of a causal relationship between reduced levels of sclerostin and improved bone health and fracture protection, but increased risk of cardiovascular events and risk factors.

Multi-omic human pancreatic islet endoplasmic reticulum and cytokine stress response mapping provides type 2 diabetes genetic insights

Endoplasmic reticulum (ER) and inflammatory stress responses contribute to islet dysfunction in type 2 diabetes (T2D). Comprehensive genomic understanding of these human islet stress responses and whether T2D-associated genetic variants modulate them is lacking. Here, comparative transcriptome and epigenome analyses of human islets exposed ex vivo to these stressors revealed 30% of expressed genes and 14% of islet cis-regulatory elements (CREs) as stress responsive, modulated largely in an ER- or cytokine-specific fashion. T2D variants overlapped 86 stress-responsive CREs, including 21 induced by ER stress. We linked the rs6917676-T T2D risk allele to increased islet ER-stress-responsive CRE accessibility and allele-specific β cell nuclear factor binding. MAP3K5, the ER-stress-responsive putative rs6917676 T2D effector gene, promoted stress-induced β cell apoptosis. Supporting its pro-diabetogenic role, MAP3K5 expression correlated inversely with human islet β cell abundance and was elevated in T2D β cells. This study provides genome-wide insights into human islet stress responses and context-specific T2D variant effects.

Evaluating the relationship between glycemic control and bone fragility within the UK Biobank: observational and one-sample Mendelian randomization analyses

We aimed to: (1) examine the relationship between glycemic control, BMD estimated from heel ultrasound (eBMD) and fracture risk in individuals with type 1 (T1D) and type 2 diabetes (T2D) and (2) perform a one-sample Mendelian randomization (MR) study to explore potential causal associations between glycemic control, eBMD, and fractures. This study comprised 452 131 individuals from the UK Biobank with glycated hemoglobin A1C (HbA1c) and eBMD levels. At baseline, 4078 participants were diagnosed with T1D and 23 682 with T2D. HbA1c was used to classify patients into "adequately-" (ACD; n = 17 078; HbA1c < 7.0%/53 mmol/mol) and "inadequately-" (ICD; n = 10 682; HbA1c ≥ 7.0%/53 mmol/mol) controlled diabetes. In individuals with T1D, a 1% unit (11 mmol/mol) increase in HbA1c levels was associated with a 12% increase in fracture risk (HR: 1.12, 95% CI [1.05-1.19]). Fracture risk was highest in individuals with T1D and ICD (HR 2.84, 95%CI [2.53, 3.19]), followed by those with ACD (HR 2.26, 95%CI [1.91, 2.69]), as compared to subjects without diabetes. Evidence for a non-linear association between HbA1c and fracture risk was observed (F-test ANOVA p-value = 0.002) in individuals with T2D, with risk being increased at both low and high levels of HbA1c. Fracture risk between the T2D ACD and ICD groups was not significantly different (HR: 0.97, 95%CI [0.91-1.16]), despite increased BMD. In MR analyses genetically predicted higher HbA1c levels were not significantly associated with fracture risk (causal risk ratio: 1.04, 95%CI [0.95-1.14]). We did observe evidence of a non-linear causal association with eBMD (quadratic test p-value = 0.0002), indicating U-shaped relationship between HbA1c and eBMD. We obtained evidence that lower HbA1c levels will reduce fracture risk in patients with T1D. In individuals with T2D, lowering HbA1c levels can mitigate the risk of fractures up to a threshold, beyond which the risk may begin to rise again.

Valid inference for machine learning-assisted genome-wide association studies

Machine learning (ML) has become increasingly popular in almost all scientific disciplines, including human genetics. Owing to challenges related to sample collection and precise phenotyping, ML-assisted genome-wide association study (GWAS), which uses sophisticated ML techniques to impute phenotypes and then performs GWAS on the imputed outcomes, have become increasingly common in complex trait genetics research. However, the validity of ML-assisted GWAS associations has not been carefully evaluated. Here, we report pervasive risks for false-positive associations in ML-assisted GWAS and introduce Post-Prediction GWAS (POP-GWAS), a statistical framework that redesigns GWAS on ML-imputed outcomes. POP-GWAS ensures valid and powerful statistical inference irrespective of imputation quality and choice of algorithm, requiring only GWAS summary statistics as input. We employed POP-GWAS to perform a GWAS of bone mineral density derived from dual-energy X-ray absorptiometry imaging at 14 skeletal sites, identifying 89 new loci and revealing skeletal site-specific genetic architecture. Our framework offers a robust analytic solution for future ML-assisted GWAS.

Mendelian randomization did not support the causal effect of diabetes on aortic diseases

Observational studies revealed paradoxically inverse associations between diabetes and aortic diseases (aortic aneurysm or aortic dissection), yet the causality remains to be determined. To investigate the causal associations between diabetes and aortic diseases using Mendelian randomization (MR) analyses. Summary-level data for exposures (type 1 diabetes, type 2 diabetes, fasting glucose, fasting insulin, glycated hemoglobin) and outcomes (aortic dissection and aortic aneurysm) were obtained from public genome-wide association study data. The principal analysis was the inverse-variance weighted (IVW) method. Sensitivity analyses were also carried out, including weighted median, MR-Egger, and multivariable MR methods. According to IVW results, type 1 diabetes (odds ratio [OR]: 0.99; 95% confidence interval [CI] 0.93-1.07; P = 0.87), type 2 diabetes (OR: 0.97; 95% CI 0.77-1.20; P = 0.75), fasting glucose (OR: 1.16; 95% CI 0.48-2.84; P = 0.74), fasting insulin (OR: 2.75; 95% CI 0.53-14.26; P = 0.23), or glycated hemoglobin (OR: 0.33; 95% CI 0.09-1.17; P = 0.09) had no causal effect on aortic dissection. Similarly, type 1 diabetes, type 2 diabetes, fasting glucose, fasting insulin, or glycated hemoglobin had no causal effect on aortic aneurysm. Sensitivity analyses revealed consistent results. MR-Egger method and funnel plot yielded no indication of directional pleiotropy. Diabetes had no causal associations with aortic dissection or aortic aneurysm. The observed inverse associations in previous cohort studies may be explained by confounding factors or reverse causation.

Likely causal effects of insulin resistance and IGF-1 bioaction on childhood and adult adiposity: a Mendelian randomization study

BACKGROUND

Circulating insulin and insulin-like growth factor-1 (IGF-1) concentrations are positively correlated with adiposity. However, the causal effects of insulin and IGF-1 on adiposity are unclear.

METHODS

We performed two-sample Mendelian randomization analyses to estimate the likely causal effects of fasting insulin and IGF-1 on relative childhood adiposity and adult body mass index (BMI). To improve accuracy and biological interpretation, we applied Steiger filtering (to avoid reverse causality) and 'biological effect' filtering of fasting insulin and IGF-1 associated variants.

RESULTS

Fasting insulin-increasing alleles (35 variants also associated with higher fasting glucose, indicative of insulin resistance) were associated with lower relative childhood adiposity (P = 3.8 × 10-3) and lower adult BMI (P = 1.4 × 10-5). IGF-1-increasing alleles also associated with taller childhood height (351 variants indicative of greater IGF-1 bioaction) showed no association with relative childhood adiposity (P = 0.077) or adult BMI (P = 0.562). Conversely, IGF-1-increasing alleles also associated with shorter childhood height (306 variants indicative of IGF-1 resistance) were associated with lower relative childhood adiposity (P = 6.7 × 10-3), but effects on adult BMI were inconclusive.

CONCLUSIONS

Genetic causal modelling indicates negative effects of insulin resistance on childhood and adult adiposity, and negative effects of IGF-1 resistance on childhood adiposity. Our findings demonstrate the need to distinguish between bioaction and resistance when modelling variants associated with biomarker concentrations.

NK2R control of energy expenditure and feeding to treat metabolic diseases

The combination of decreasing food intake and increasing energy expenditure represents a powerful strategy for counteracting cardiometabolic diseases such as obesity and type 2 diabetes1. Yet current pharmacological approaches require conjugation of multiple receptor agonists to achieve both effects2-4, and so far, no safe energy-expending option has reached the clinic. Here we show that activation of neurokinin 2 receptor (NK2R) is sufficient to suppress appetite centrally and increase energy expenditure peripherally. We focused on NK2R after revealing its genetic links to obesity and glucose control. However, therapeutically exploiting NK2R signalling has previously been unattainable because its endogenous ligand, neurokinin A, is short-lived and lacks receptor specificity5,6. Therefore, we developed selective, long-acting NK2R agonists with potential for once-weekly administration in humans. In mice, these agonists elicit weight loss by inducing energy expenditure and non-aversive appetite suppression that circumvents canonical leptin signalling. Additionally, a hyperinsulinaemic-euglycaemic clamp reveals that NK2R agonism acutely enhances insulin sensitization. In diabetic, obese macaques, NK2R activation significantly decreases body weight, blood glucose, triglycerides and cholesterol, and ameliorates insulin resistance. These findings identify a single receptor target that leverages both energy-expending and appetite-suppressing programmes to improve energy homeostasis and reverse cardiometabolic dysfunction across species.

Using Genetics to Assess the Role of Acetate in Ischemic Heart Disease, Diabetes, and Sex-Hormone-Related Cancers: A Mendelian Randomization Study

BACKGROUND

Acetate, a short-chain fatty acid, has gained attention for its contrasting roles, with evidence suggesting it may offer cardiovascular protection but also promote cancer, particularly those involving sex hormones. However, these influences have been scarcely assessed in epidemiological research.

OBJECTIVE

To investigate the relationship between acetate and ischemic heart disease (IHD), diabetes, and cancers related to sex hormones.

METHODS

Mendelian randomization (MR) was used to assess potential causal effects, selecting genetic variants without linkage disequilibrium (r2 < 0.001) and with genome-wide significance for acetate (p < 5 × 10-8). These variants were applied to large genome-wide association studies (GWAS) for ischemic heart disease (IHD; up to 154,373 cases), diabetes (109,731 cases), and five sex-hormone-related cancers (breast, colorectal, prostate, ovarian, and endometrial cancers, ranging from 8679 to 122,977 cases). We employed various methods for analysis, including penalized inverse variance weighting (pIVW), inverse variance weighting, weighted mode, and weighted median.

RESULTS

This study indicates that acetate may be associated with a lower risk of ischemic heart disease (IHD), with an odds ratio (OR) of 0.62 per standard deviation (SD) increase in acetate and a 95% confidence interval (CI) of 0.39 to 0.98. Additionally, acetate was linked to a higher breast cancer risk, with an OR of 1.26 and a 95% CI ranging from 1.08 to 1.46. This association remained robust across multiple sensitivity analyses.

CONCLUSIONS

Acetate, along with factors that influence its activity, may serve as possible targets for breast cancer treatment and possibly IHD, offering opportunities for new drug development.

Common- and rare-variant genetic architecture of heart failure across the allele frequency spectrum

Heart failure (HF) is a complex trait, influenced by environmental and genetic factors, which affects over 30 million individuals worldwide. Historically, the genetics of HF have been studied in Mendelian forms of disease, where rare genetic variants have been linked to familial cardiomyopathies. More recently, genome-wide association studies (GWAS) have successfully identified common genetic variants associated with risk of HF. However, the relative importance of genetic variants across the allele-frequency spectrum remains incompletely characterized. Here, we report the results of common- and rare-variant association studies of all-cause heart failure, applying recently developed methods to quantify the heritability of HF attributable to different classes of genetic variation. We combine GWAS data across multiple populations including 207,346 individuals with HF and 2,151,210 without, identifying 176 risk loci at genome-wide significance (P-value < 5×10-8). Signals at newly identified common-variant loci include coding variants in Mendelian cardiomyopathy genes (MYBPC3, BAG3) and in regulators of lipoprotein (LPL) and glucose metabolism (GIPR, GLP1R). These signals are enriched in myocyte and adipocyte cell types and can be clustered into 5 broad modules based on pleiotropic associations with anthropomorphic traits/obesity, blood pressure/renal function, atherosclerosis/lipids, immune activity, and arrhythmias. Gene burden studies across three biobanks (PMBB, UKB, AOU), including 27,208 individuals with HF and 349,126 without, uncover exome-wide significant (P-value < 1.57×10-6) associations for HF and rare predicted loss-of-function (pLoF) variants in TTN, MYBPC3, FLNC, and BAG3. Total burden heritability of rare coding variants (2.2%, 95% CI 0.99-3.5%) is highly concentrated in a small set of Mendelian cardiomyopathy genes, while common variant heritability (4.3%, 95% CI 3.9-4.7%) is more diffusely spread throughout the genome. Finally, we show that common-variant background, in the form of a polygenic risk score (PRS), significantly modifies the risk of HF among carriers of pathogenic truncating variants in the Mendelian cardiomyopathy gene TTN. Together, these findings provide a genetic link between dysregulated metabolism and HF, and suggest a significant polygenic component to HF exists that is not captured by current clinical genetic testing.

Genetic architecture of routinely acquired blood tests in a British South Asian cohort

Understanding the genetic basis of routinely-acquired blood tests can provide insights into several aspects of human physiology. We report a genome-wide association study of 42 quantitative blood test traits defined using Electronic Healthcare Records (EHRs) of ~50,000 British Bangladeshi and British Pakistani adults. We demonstrate a causal variant within the PIEZO1 locus which was associated with alterations in red cell traits and glycated haemoglobin. Conditional analysis and within-ancestry fine mapping confirmed that this signal is driven by a missense variant - chr16-88716656-G-TT - which is common in South Asian ancestries (MAF 3.9%) but ultra-rare in other ancestries. Carriers of the T allele had lower mean HbA1c values, lower HbA1c values for a given level of random or fasting glucose, and delayed diagnosis of Type 2 Diabetes Mellitus. Our results shed light on the genetic basis of clinically-relevant traits in an under-represented population, and emphasise the importance of ancestral diversity in genetic studies.