Assessing causality between osteoarthritis with urate levels and gout: a bidirectional Mendelian randomization study

Assessing Causality Between Second-Hand Smoking and Potentially Associated Diseases in Multiple Systems: A Two-Sample Mendelian Randomization Study

INTRODUCTION

The global disease burden may be exacerbated by exposure to passive smoking (SHS), with the workplace being a primary location for such exposure. Numerous epidemiological studies have identified SHS as a risk factor for diseases affecting various systems, including cardiovascular, respiratory, immune, endocrine, and nervous systems. The conventional observational study has certain methodological constraints that can be circumvented through a Mendelian randomization (MR) study. Our MR study intends to investigate the causal link between workplace exposure to SHS and the potential associated diseases.

AIM AND METHODS

Summary statistics data involving European participants were sourced from three databases: the UK Biobank, the FinnGen study, and the European Bioinformatics Institute. Genetic variants linked with exposure to SHS in the workplace were identified as instrumental variables. The MR was carried out using inverse variance weighted (IVW), MR-Egger, and weighted median methods. Sensitivity tests were also undertaken within the MR to evaluate the validity of the causality.

RESULTS

According to the IVW model, genetically determined atrial fibrillation (AF) and stroke (p = 6.64E-04 and 5.68E-07, odds ratio = 2.030 and 2.494, 95% confidence interval = 1.350 to 3.051 and 1.743 to 3.569) were robustly associated with exposure to SHS in the workplace. Suggestive associations were found between workplace SHS and myocardial infarction (MI), asthma, and depression.

CONCLUSIONS

The MR study demonstrates that exposure to SHS in the workplace is a significant risk factor for AF and stroke in European individuals. Whether workplace exposure to SHS influences other diseases and the causality between them requires further exploration.

IMPLICATIONS

This study explored the causality between exposure to SHS in the workplace and potential associated diseases in multiple systems, including MI, AF, stroke, lung cancer, asthma, allergic disease, type 2 diabetes, and depression, using an MR study. The MR study can circumvent the methodological constraints of observational studies and establish a causal relationship. The two-sample MR analysis provides evidence supporting the causal association of frequent workplace SHS with AF and stroke. Individuals exposed to SHS in the workplace may also have a heightened risk of MI, asthma, and depression. However, whether SHS affects other diseases and the causality between them requires further investigation. To our knowledge, this is the first two-sample MR study to determine the causal relationship between SHS and potential diseases. Exposure to SHS in the workplace is a prevalent issue and may contribute to a global disease burden. The reduction of exposure following the introduction of smoke-free laws has led to a decrease in the admission rate for cardiac events and an improvement in health indicators. It is crucial to further advance smoke-free policies and their implementation.

Potential drug targets for tumors identified through Mendelian randomization analysis

According to the latest cancer research data, there are a significant number of new cancer cases and a substantial mortality rate each year. Although a substantial number of clinical patients are treated with existing cancer drugs each year, the efficacy is unsatisfactory. The incidence is still high and the effectiveness of most cancer drugs remains unsatisfactory. Therefore, we evaluated the human proteins for their causal relationship to for cancer risk and therefore also their potential as drug targets. We used summary tumors data from the FinnGen and cis protein quantitative trait loci (cis-pQTL) data from a genome-wide association study, and employed Mendelian randomization (MR) to explore the association between potential drug targets and nine tumors, including breast, colorectal, lung, liver, bladder, prostate, kidney, head and neck, pancreatic caners. Furthermore, we conducted MR analysis on external cohort. Moreover, Bidirectional MR, Steiger filtering, and colocalization were employed to validate the main results. The DrugBank database was used to discover potential drugs of tumors. Under the threshold of False discovery rate (FDR) < 0.05, results showed that S100A16 was protective protein and S100A14 was risk protein for human epidermal growth factor receptor 2-positive (HER-positive) breast cancer, phosphodiesterase 5A (PDE5A) was risk protein for colorectal cancer, and melanoma inhibitory activity (MIA) was protective protein for non-small cell lung carcinoma (NSCLC). And there was no reverse causal association between them. Colocalization analysis showed that S100A14 (PP.H4.abf = 0.920) and S100A16 (PP.H4.abf = 0.932) shared causal variation with HER-positive breast cancer, and PDE5A (PP.H4.abf = 0.857) shared causal variation with colorectal cancer (CRC). The MR results of all pQTL of PDE5A and MIA were consistent with main results. In addition, the MR results of MIA and external outcome cohort were consistent with main results. In this study, genetic predictions indicate that circulating S100 calcium binding protein A14 (S100A14) and S100 calcium binding protein A16 (S100A16) are associated with increase and decrease in the risk of HER-positive breast cancer, respectively. Circulating PDE5A is associated with increased risk of CRC, while circulating MIA is associated with decreased risk of NSCLC. These findings suggest that four proteins may serve as biomarkers for cancer prevention and as potential drug targets that could be expected for approval.

Genetically determined metabolites in allergic conjunctivitis: A Mendelian randomization study

Background

Allergic conjunctivitis (AC) afflicts a significant portion of the global populace. Yet, its metabolic foundations remain largely unexplored.

Methods

We applied Mendelian Randomization (MR) and Linkage Disequilibrium Score Regression (LDSC) to scrutinize a cohort comprising 20 958 AC cases and 356 319 controls. Data were amalgamated from the metabolomics GWAS server and the FinnGen project, under strict quality control protocols.

Results

Using two-sample MR analysis, 486 blood metabolites were investigated in relation to AC. The IVW approach highlighted 18 metabolites as closely tied to AC risk; of these, 16 retained significance post sensitivity assessments for heterogeneity and horizontal pleiotropy. LDSC analysis, adopted to bolster our findings and negate confounders from shared genetic markers, revealed 8 metabolites with marked heritability, including: palmitate (OR = 0.614), 3-methoxytyrosine (OR = 0.657), carnitine (OR = 1.368), threonate (OR = 0.828), N-[3-(2-Oxopyrrolidin-1-yl)propyl]acetamide (OR = 1.257), metoprolol acid metabolite (OR = 0.982), oleoylcarnitine (OR = 0.635), and 2-palmitoylglycerophosphocholine (OR = 1.351).

Conclusion

AC is precipitated by ocular responses to environmental allergens. Our study unveils a causal link between 8 blood metabolites and AC. This insight accentuates the role of metabolites in AC onset, suggesting novel avenues for its early prediction, targeted prevention, and tailored therapeutic interventions.

Osteoarthriris year in review 2023: genetics, genomics, and epigenetics

OBJECTIVE

To elucidate the scientific advances made in the last 12 months within the realm of osteoarthritis genetics, genomics, and epigenetics. This review paper highlights major research publications that enhance our current understanding of the role of genetics, genomics, and epigenetics in osteoarthritis.

METHODS

A systematic literature search was conducted on pubmed.ncbi.nlm.nih.gov on "March 17, 2023", using the following keywords: "osteoarthritis" in combination with any of these terms: "genetic(s)", "mutation(s)", "genomic(s)", "epigenetic(s)", "DNA methylation", "noncoding RNA", "lncRNA", "circular RNA", "microRNA", "transcriptomic(s)", "RNA sequencing", "single cell RNA sequencing", or "single nucleus RNA sequencing". The selection comprised original research articles published in the English language between the OARSI congresses of 2022 and 2023.

RESULTS

A total of 2178 research articles were identified, which subsequently reduced to 67 unique articles relevant to the field. Current trends in osteoarthritis genetics research involve meta-analyses of various cohorts to explore the impact of gene variants on osteoarthritis-related outcomes, such as pain. Early developmental changes within the joint were also found to influence osteoarthritis through genetic variations. Researchers also prioritize testing the mechanisms and functions of miRNAs, circRNAs, and lncRNAs. Potential drug targets began to emerge; however, independent validation studies are lacking. Single cell RNA sequencing studies revealed unique immune cell populations in the knee; however, no study reported single nucleus RNA sequencing analysis.

CONCLUSIONS

This review focused on recent advances in the above-mentioned themes within the field of osteoarthritis. These advances improve our understanding of the disease's complexity and guide us toward functional assessments of genetic/epigenetic outcomes and toward their translational and clinical applications.

The causal relationship between osteoarthritis and bladder cancer: A Mendelian randomization study

OBJECTIVE

The causal association between osteoarthritis (OA) and bladder cancer remains unclear. This Mendelian randomization (MR) study was carried out to assess the potential causal effects of any OA, knee OA and hip OA, and bladder cancer.

METHOD

Genome-wide association study (GWAS) summary data for OA and bladder cancer were obtained in GWAS CATALOG, UK Biobank, and FinnGen Consortium. Inverse-variance weighted (IVW) approach was primarily conducted to evaluate the causal relationships between OA and bladder cancer, and MR-Egger intercept and Cochran's Q test were mainly used to estimate heterogeneity and pleiotropy. MR-PRESSO was used to test the presence of horizontal outliers. Leave-one-out analysis was utilized to ensure the reliability of the results.

RESULTS

A higher genetic predisposition to any OA has a causal association with bladder cancer risk, while neither knee OA nor hip OA is causally linked to bladder cancer. MR-Egger intercept analysis exhibited that any OA and knee OA had no pleiotropic effect on the risk of bladder cancer, and Cochran's Q test showed that any OA, knee OA and hip OA had no heterogeneity on bladder cancer risk. Neither MR PRESSO analysis nor leave-one-out analysis revealed any outlier SNPs.

CONCLUSIONS

This MR study exhibited a positive cause-and-effect relationship between any type of OA and bladder cancer risk, but not between site-specific OA, knee OA and hip OA, and bladder cancer. Attention should be paid to the screening and prevention of bladder cancer in OA patients at any site.

Exploring the genetic association of allergic diseases with cardiovascular diseases: a bidirectional Mendelian randomization study

Background

In observational and experimental studies, allergic diseases (AD) have been reported to be associated with some types of cardiovascular diseases (CVD), as both share common pathophysiological processes involving inflammation and metabolic disorders. However, the direction of the causal association between them remains unclear. This Mendelian randomization (MR) study aims to examine the bidirectional causality between AD and CVD.

Methods

We utilized publicly available genome-wide association study (GWAS) summary statistics data from European participants in the UK Biobank and the IEU Open GWAS database. Genetic variants associated with AD, asthma, and CVD were identified and used as instrumental variables to investigate the genetically causal association between them. MR analyses were performed using various analytical methods, including inverse variance weighted-fixed effects (IVW-FE), inverse variance weighted-multiplicative random effects (IVW-RE), MR-Egger, weighted median, weighted mode, and maximum likelihood. Sensitivity tests were conducted to assess the validity of the causality.

Results

The MR analysis with the IVW method revealed a genetically predicted association between AD and essential hypertension [odds ratio (OR)=0.9987, 95% confidence interval (CI): 0.9976-0.9998, P=0.024], as well as between asthma and atrial fibrillation (OR=1.001, 95% CI: 1.0004-1.0017, P=6.43E-05). In the reverse MR analyses, heart failure was associated with allergic diseases (OR=0.0045, 95% CI: 1.1890E-04 - 0.1695, P=0.004), while atherosclerosis (OR=8.7371E-08, 95% CI: 1.8794E-14 - 4.0617E-01, P=0.038) and aortic aneurysm and dissection (OR=1.7367E-07, 95% CI: 3.8390E-14 - 7.8567E-01, P=0.046) might be protective factors of asthma. However, after a Bonferroni correction, only the association between asthma and atrial fibrillation remained robust.

Conclusion

The MR study revealed that asthma is a predominant risk of atrial fibrillation in European individuals, consistent with most experimental and observational studies. Whether AD affects other CVD and the causality between them needs further investigation.

Causal relationships between serum matrix metalloproteinases and estrogen receptor-negative breast cancer: a bidirectional mendelian randomization study

To better clarify the causal effects between matrix metalloproteinases (MMPs) and estrogen-receptor (ER)-negative breast cancer (BC), we investigated the bidirectional causal relationship between MMPs and ER-negative BC by mendelian randomization (MR) analysis. Summary statistic data of five MMPs were extracted from European participants in 13 cohorts. Data of ER-negative BC collected from one of genome-wide association studies of European ancestry was used as experimental datasets and another four ER-negative BC datasets were used as validation sets. Inverse variance weighted method was used for main MR analysis and sensitivity analysis was also conducted. Serum level of MMP-1 has negative effect on ER-negative BC (odds ratio = 0.92, P = 0.0008) but the latter one was not the cause of the former one, which was supported by validation sets. No bidirectional causal effect was detected between the other four types of MMPs and ER-negative BC (P > 0.05). Sensitivity analysis indicated robustness of the above results without remarkable bias. To conclude, serum MMP-1 may be a protective factor against ER-negative BC. No reciprocal causality was found between the other kinds of MMPs and ER-negative BC. MMP-1 was indicated as a biomarker for risk of ER-negative BC.