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Human skin microbiota and postpartum depression: A bidirectional Mendelian randomization study.

Postpartum depression (PPD) is a common mental health disorder after childbirth. Although microbiome research in PPD has mainly focused on the gut, the role of skin microbiota remains unclear. We used Mendelian randomization (MR) to assess potential causal associations between skin microbiota and PPD. A bidirectional 2-sample MR analysis used genome-wide association study (GWAS) summary statistics. Genetic instruments for skin microbial features were obtained from a published skin microbiota GWAS, and PPD data were derived from 67,205 mothers (7604 cases, 59,601 controls). Instruments were selected at P&#x2005;<1&#x2005;&#xd7;&#x2005;10-5, linkage disequilibrium-clumped, harmonized, and filtered for weak instruments (F statistic&#x2005;<10). Because this microbiome threshold is exploratory, Benjamini-Hochberg false discovery rate correction was applied within taxonomic levels. The inverse-variance weighted method was primary, complemented by weighted median and mode-based methods. Heterogeneity, pleiotropy, and outliers were assessed using Cochran Q, MR-Egger intercept, and MR-PRESSO. Three skin microbial taxa showed nominal associations with PPD. Higher genetically predicted Acinetobacter on the dorsal forearm (dry skin; 9 single nucleotide polymorphisms [SNPs]; mean F&#x2005;=&#x2005;22.12) and Proteobacteria in the antecubital fossa (moist skin; 6 SNPs; mean F&#x2005;=&#x2005;23.44) were associated with increased PPD risk, whereas Betaproteobacteria in the antecubital fossa (11 SNPs; mean F&#x2005;=&#x2005;21.54) was associated with decreased risk. Associations were directionally consistent, with no substantial heterogeneity or horizontal pleiotropy. After multiple-testing assessment, the findings were exploratory rather than definitive. Reverse MR did not support an effect of PPD on the identified skin microbiota. This MR study provides exploratory genetic evidence linking specific skin microbial features to PPD risk. The findings extend microbiota-related hypotheses beyond the gut microbiome but require validation in larger microbiome GWAS datasets, longitudinal cohorts, and mechanistic studies before clinical or causal conclusions are drawn.

Humans↗

Migraine is not a risk factor for glaucoma: Evidence from a bidirectional Mendelian randomization study.

Numerous compelling observational studies have indicated that migraine is a risk factor for the development of glaucoma. Nevertheless, some studies have observed entirely opposite results. The objective of our research is to evaluate the potential relationship between migraine and glaucoma by employing a bidirectional Mendelian Randomization (MR) approach. This method enables us to rigorously assess the causal links between these 2 conditions, thereby addressing the discrepancies in existing literature. Independent genetic variants associated with glaucoma and migraine at the genome-wide significance level were selected as instrumental variables. All summary data were obtained from the genome-wide association study database. The primary method employed in the bidirectional MR analysis was the inverse variance weighted method, while sensitivity analyses utilized the leave-one-out method, MR-Egger method, and MR-Pleiotropy RESidual Sum and Outlier&#x200c; method. When migraine and its subtypes (specifically migraine with aura and migraine without aura) were evaluated as exposure factors, we found no evidence of a causal relationship with glaucoma and its subtypes (namely angle-closure glaucoma and open-angle glaucoma). Subsequently, in the reverse MR analysis, when glaucoma and its subtypes (angle-closure glaucoma and open-angle glaucoma) were assessed as exposure factors, there was no substantial evidence to support a causal relationship with migraine or its subtypes (migraine with aura and migraine without aura). Furthermore, sensitivity analyses also reinforced the robustness of our bidirectional MR findings. Our bidirectional MR analysis mitigates the biases associated with traditional observational studies, highlighting that there is no direct causal relationship between migraine and the risk of glaucoma.

Humans↗

Identifying novel protein biomarkers with cross-psychiatric disorders effects and potential intervention targets: Evidence from proteomic-Mendelian randomization.

Plasma proteins are the potential therapeutic targets for psychiatric disorders due to their important roles in signal transduction. We aimed to explore the plasma protein biomarkers with cross-psychiatric disorders effects. Proteome-wide Mendelian randomization (MR) and colocalization analyses were performed to investigate the potential causal relationship between plasma protein biomarkers and 12 psychiatric disorders and further identify the potential proteins with cross-effects. To assess the directionality and exclude potential reverse causation, Steiger directionality tests and reverse MR analyses were additionally conducted. Then, validation analysis was performed by employing summary data from cross-psychiatric disorder GWAS to validate the cross-psychiatric effects of proteins. Protein-protein interactions were conducted to evaluate the interaction between candidate proteins and druggability assessment was used to prioritize potential drug targets for psychiatric disorders. We identified novel plasma proteins that possessed cross-psychiatric disorder effects, especially BTN2A1 and BTN3A2 associated with major depressive disorder (MDD), schizophrenia (SCZ), and bipolar disorder (BIP); ITIH1, ITIH3, ITIH4 and FES associated with SCZ and BIP, and the cross-effects of these proteins on SCZ and BIP were confirmed by validation analyses. Steiger tests and reverse MR supported causal directionality. Besides, the protein-protein interactions (PPI) analysis indicated cross-effects proteins had significant interaction, especially ITIH1-ITIH3. The druggability assessment prioritized eight proteins, two of which (ITIH3 and NCAM1) has been targeted by antipsychotic drugs. Our findings provided insights into shared biological mechanisms underlying these conditions.

Humans↗

Microglial PICALM: A novel genetic driver and therapeutic target in vascular dementia.

BACKGROUND: Vascular dementia (VaD) lacks well-defined genetic mechanisms. Cell-type-specific effects of GWAS loci remain unexplored. METHODS: We integrated single&#x2011;cell eQTL data (183 donors, eight cell types) with VaD GWAS (3624 cases, 475,484 controls) using Mendelian randomization and Bayesian colocalization, replicated in an independent cohort (2074 cases, 456,366 controls). Subtype, snRNA&#x2011;seq, cell&#x2011;cell communication, PheWAS, expression profiling, and drug prediction with BBB permeability assessment were performed. RESULTS: Microglial PICALM was the only robustly replicated signal (OR = 0.8334, p = 5.3 &#xd7; 10&#x207b;&#x2074;; colocalization PP.H4 > 0.75). The effect was strongest in multiple infarctions dementia (OR = 0.7746). Exploratory snRNA-seq analysis (4 VaD vs. 4 controls; GSE282111) provided supporting evidence for microglial PICALM enrichment and downregulation (p < 0.001). PICALM&#x2011;high microglia showed enhanced neurovascular&#x2011; and phagocytosis&#x2011;related communication (e.g., SPP1, GAS6, GRN). PheWAS revealed no pleiotropy. In silico drug repurposing prioritised three FDA-approved BBB-penetrant compounds (disopyramide, benzocaine, amantadine) as candidates warranting further mechanistic validation. CONCLUSIONS: Microglial PICALM is identified as a likely genetic determinant of VaD, especially in the multiple infarctions subtype. Upregulating PICALM may be associated with a neuroprotective microglial phenotype, highlighting PICALM as a candidate therapeutic target warranting further experimental validation.

Humans↗

Potential mitochondria-associated pathogenic genes in sepsis: a multi-omics Mendelian randomization study.

BACKGROUND: Mitochondrial dysfunction has been implicated in the pathophysiology of sepsis. However, human genetic evidence linking mitochondria-related genes to sepsis susceptibility remains limited. This study aimed to identify mitochondria-related genes associated with sepsis risk using a multi-omics Mendelian randomization framework. METHODS: Summary-data-based Mendelian randomization (SMR) was applied using sepsis genome-wide association study (GWAS) summary statistics from the UK Biobank and FinnGen databases. Expression, methylation, single-cell, and protein quantitative trait loci (QTLs) were used as genetic instruments. Colocalization analyses were conducted to evaluate whether SMR associations were driven by shared genetic variants. Expression of prioritized candidate genes was further examined in clinical septic samples, and correlations with disease severity (SOFA scores) were assessed. RESULTS: SMR analysis prioritized 13 mitochondria-related genes associated with sepsis risk. Immune cell-specific eQTL analysis suggested that genetically predicted SURF1 expression in memory B cells and na&#xef;ve T cells was associated with sepsis risk. Differential expression of 12 candidate genes was confirmed in septic patients by qPCR, and PPOX expression showed a negative correlation with SOFA scores. Integration of mQTL and eQTL data supported a regulatory relationship between methylation at cg06661924 and AK4 expression. Increased genetically predicted AK4 expression was associated with higher sepsis risk (OR&#xa0;=&#xa0;1.21, 95% CI 1.02-1.42). Protein-level analysis identified DUT as a potential sepsis-associated candidate, with consistent evidence across streptococcal and pneumococcal septicemia subtypes. Subtype analyses also suggested heterogeneous genetic signals across different sepsis subtypes. CONCLUSION: This study prioritized several mitochondria-related genes associated with sepsis susceptibility based on human genetic evidence. These findings provide candidate targets for further mechanistic and translational investigation.

Humans↗

CAUSAL ASSOCIATION BETWEEN SEPSIS AND FIBROBLAST GROWTH FACTORS AS WELL AS THEIR RECEPTORS LEVELS: A TWO-SAMPLE MENDELIAN RANDOMIZATION STUDY.

Objective: The potential association between sepsis risk and circulating levels of fibroblast growth factors (FGFs) and their receptors (FGFRs) has been a focus of research; however, the causal relationship between them remains to be elucidated. We hypothesize a causal association between genetically predicted FGFs, FGFRs, and sepsis risk, and we conduct a Mendelian randomization (MR) study to validate this hypothesis. Methods: We utilized a two-sample MR design to assess the effect of genetic variants associated with various FGFs (FGF1, FGF2, FGF7, FGF16, FGF19, FGF21, FGF23, FGF5) and FGFRs (FGFR1, FGFR2, FGFR3, &#x3b1;-Klotho) on sepsis risk, using genome-wide association study summary statistics. Our MR analyses employed the inverse-variance weighted (IVW) method, along with weighted median, weighted mode, and MR-Egger regression, supplemented by sensitivity analyses to ensure robustness. Results: The MR analysis identified an unequal number of instrumental variables ranging from 2 to 17 for FGFs and FGFRs when sepsis was the outcome. No significant correlation was found between genetically determined FGF levels and sepsis risk by IVW analysis (all P > 0.05). Correspondingly, similar nonsignificant associations were observed for FGFRs (all P > 0.05). Other MR methods corroborated the IVW findings. Sensitivity analyses, including Cochran's Q test, MR-Egger, and MR pleiotropy residual sum and outlier, indicated no significant heterogeneity or pleiotropy in the relationships, with the exception of a nonsignificant correlation between FGFR1 and sepsis that persisted after the exclusion of an outlier (odds ratio, 0.84; P = 0.34). Conclusion: The analysis found no significant causal associations between FGFs, their receptors, and sepsis risk, indicating a need for further research on their complex interactions.

Humans↗

Is impulsivity simply a failure of self-control? Evidence based on multi-omics analyses of genomics, metabolomics and brain imaging.

High impulsivity-a hallmark of various adverse life outcomes such as substance abuse, impulsive buying, violence, and crime-has typically been considered as a failure of self-control. However, is impulsivity simply a failure of self-control? To address this issue, we employed multi-omics combined with brain imaging approach in a large-scale sample (Nbrain imaging=1524, Ngenomics=835, Nmetabolomics=946) to elucidate the relationship between impulsivity and self-control. Mendelian randomization showed a bidirectional association between impulsivity and self-control, suggesting that they influenced each other. Partial least squares analysis highlighted that self-control primarily implicates the frontal lobe regions (e.g., superior frontal gyrus), whereas impulsivity involves the amygdala, insula, and basal ganglia. The cerebellum, superior frontal gyrus, and middle frontal gyrus were identified as shared areas in impulsivity and self-control. Furthermore, gene-based association analysis identified heterochromatin protein 1 binding protein 3 as specifically related to impulsivity, while pathway enrichment analysis demonstrated that arginine and proline metabolism was a common metabolic pathway associated with both impulsivity and self-control. Overall findings demonstrate that impulsivity and self-control involve both shared and distinct brain regions, genetic and metabolic foundations. The brain imaging results suggest that impulsivity is related not only to self-control-related processes but also to the motivation to pursue rewards. Together, this large-scale integrative study firstly provides a side-by-side map of genomic, metabolic, and limbic-network signatures of impulsivity distinct from self-control, offering a foundation for mechanism-driven biomarker and intervention research in maladaptive impulsivity.

Impulsive Behavior↗

Genetic risk factors in rheumatoid arthritis: A Mendelian randomization study of chronic kidney disease in European populations.

Rheumatoid arthritis (RA) is a heritable autoimmune disease linked to chronic kidney disease (CKD) in observational studies. However, whether this association is causal and driven by shared genetic risk remains unclear, warranting genetic investigation. To investigate possible causal relationships between RA and different CKD subtypes, we used Mendelian randomization (MR) analyses with data from genome-wide association studies. The inverse variance weighted (IVW) methodology was the main method, and sensitivity analyses were added to improve the validity of the causal estimations. Our analysis predicted that RA significantly increases the risk of IgA nephropathy (IVW odds ratio [OR]&#x2005;=&#x2005;1.041, 95% confidence interval [CI]&#x2005;=&#x2005;1.018-1.065, P&#x2005;=&#x2005;4.286e-04), diabetic nephropathy (IVW OR&#x2005;=&#x2005;1.078, 95% CI&#x2005;=&#x2005;1.009-1.152, P&#x2005;=&#x2005;.027), nephrotic syndrome (IVW OR&#x2005;=&#x2005;1.164, 95% CI&#x2005;=&#x2005;1.078-1.257, P&#x2005;=&#x2005;1.012e-04), and chronic renal failure (IVW OR&#x2005;=&#x2005;1.046, 95% CI&#x2005;=&#x2005;1.018-1.075, P&#x2005;=&#x2005;1.000e-03). MR analyses confirmed RA's positive causal effect on these CKD subtypes (all P&#x2005;<&#x2005;.05). While heterogeneity was observed for IgA nephropathy and chronic renal failure, sensitivity analyses (MR-Egger intercept, all P&#x2005;>&#x2005;.05) revealed no evidence of horizontal pleiotropy, supporting the robustness of our findings. Our findings suggest that in European-ancestry populations, a genetic predisposition to RA is causally associated with a higher risk of specific types of CKD. While these results require validation in diverse ethnic groups, they highlight the potential importance of renal monitoring for genetically susceptible RA patients, which may help mitigate the public health burden of CKD.

Humans↗

New insights into causal relationship between serum lipids, obesity, and asthma: a Mendelian randomization study.

OBJECTIVE: To identify causal risk factors for asthma using a Mendelian randomization (MR) approach. METHODS: Genetic variants associated with the exposures at the genome-wide significance level (p&#x2009;<&#x2009;5&#x2009;&#xd7;&#x2009;10&#x2009;-&#x2009;8) were obtained from corresponding genome-wide association studies. Summary-level statistical data for asthma were obtained from the UK Biobank (UKB) and the FinnGen Consortia. Univariate and multivariate MR analyses were performed to clarify causal relationships among obesity, serum lipids, and asthma. Meta-analyses were performed to combine UKB and FinnGen results using a fixed-effects model. RESULTS: In FinnGen, the odds for asthma increased for every 1-SD increase in body mass index (BMI; odds ratio [OR] 1.292, p&#x2009;=&#x2009;1.34&#x2009;&#xd7;&#x2009;10-7), together with body fat percentage (BF%; OR 1.449, p&#x2009;=&#x2009;4.90&#xd7;10-3), and total cholesterol level (OR = 0.949, p&#x2009;=&#x2009;0.027). However, higher BMI and BF% were found to increase the risk for asthma in the multivariate MR analysis. In the UKB, the BMI results were replicated. Meta-analysis revealed that high-density lipoprotein cholesterol could also increase the risk for asthma, although there were no associations with other risk factors included in this study. CONCLUSION: This MR study found that genetically predicted higher BF% and BMI could increase the risk for asthma and corroborated some risk factors for asthma from previous MR studies. Moreover, the results suggest that higher BMI and BF% could serve as independent risk factors for asthma.

Humans↗

Risk relationship between inflammatory bowel disease and urolithiasis: A two-sample Mendelian randomization study.

BACKGROUND: The causal genetic relationship between common parenteral manifestations of inflammatory bowel disease (IBD) and urolithiasis remains unclear because their timing is difficult to determine. This study investigated the causal genetic association between IBD and urolithiasis using Mendelian randomization (MR) based on data from large population-based genome-wide association studies (GWASs). METHODS: A two-sample MR analysis was performed to assess the potential relationship between IBD and urolithiasis. Specific single nucleotide polymorphism data were obtained from GWASs, including IBD (n = 59957) and its main subtypes, Crohn's disease (CD) (n = 40266) and ulcerative colitis (UC) (n = 45975). Summarized data on urolithiasis (n = 218792) were obtained from different GWAS studies. A random-effects model was analyzed using inverse-variance weighting, MR-Egger, and weighted medians. RESULTS: Genetic predisposition to IBD and the risk of urolithiasis were significantly associated [odds ratio (OR), 1.04 (95% confidence interval [CI], 1.00-.08), P = 0.01]. Consistently, the weighted median method yielded similar results [OR, 1.06 (95% CI, 1.00-1.12), P = 0.02]. The MR-Egger method also demonstrated comparable findings [OR, 1.02 (95% CI, 0.96-1.08), P = 0.45]. Both funnel plots and MR-Egger intercepts indicated no directional pleiotropic effects between IBD and urolithiasis. CD was strongly associated with it in its subtype analysis [OR, 1.04 (95% CI, 1.01-1.07), P = 0.01], and UC was also causally associated with urolithiasis, although the association was not significant [OR, 0.99 (95% CI, 0.95-1.03), P = 0.71]. CONCLUSION: A unidirectional positive causal correlation was identified between IBD and urolithiasis, with varying degrees of association observed among the different subtypes of IBD. Recognizing the increased incidence of urolithiasis in patients with IBD is crucial in clinical practice. Early detection and surveillance of IBD, improved patient awareness, adoption of preventive strategies, and promotion of collaborative efforts among healthcare providers regarding treatment methodologies are vital for improving patient outcomes.

Humans↗

A Causal Effect of Serum 25(OH)D Level on Appendicular Muscle Mass: Evidence From NHANES Data and Mendelian Randomization Analyses.

BACKGROUND: Low serum vitamin D status was reported to be associated with reduced muscle mass; however, it is inconclusive whether this relationship is causal. This study used data from the National Health and Nutrition Examination Survey (NHANES) and two-sample Mendelian randomization (MR) analyses to ascertain the causal relationship between serum 25-hydroxyvitamin D [25(OH)D] and appendicular muscle mass (AMM). METHODS: In the NHANES 2011-2018 dataset, 11&#x2009;242 participants (5588 males and 5654 females) aged 18-59&#x2009;years old were included, and multivariant linear regression was performed to assess the relationship between 25(OH)D and AMM measured by dual-energy X-ray absorptiometry. In two-sample MR analysis, 167 single nucleotide polymorphisms significantly associated with serum 25(OH)D at the genome-wide association level (p&#x2009;<&#x2009;5&#x2009;&#xd7;&#x2009;10-8) were applied as instrumental variables (IVs) to assess vitamin D effects on AMM in the UK Biobank (417&#x2009;580 Europeans) using univariable and multivariable MR (MVMR) models. RESULTS: In the NHANES dataset, serum 25(OH)D concentrations were positively associated with AMM (&#x3b2;&#x2009;=&#x2009;0.013, SE&#x2009;=&#x2009;0.001, p&#x2009;<&#x2009;0.001) in all participants, after adjustment for age, race, season of blood collection, education, income, body mass index and physical activity. In stratification analysis by sex, males (&#x3b2;&#x2009;=&#x2009;0.024, SE&#x2009;=&#x2009;0.002, p&#x2009;<&#x2009;0.001) showed more pronounced positive associations than females (&#x3b2;&#x2009;=&#x2009;0.003, SE&#x2009;=&#x2009;0.002, p&#x2009;=&#x2009;0.024). In univariable MR, genetically higher serum 25(OH)D levels were positively associated with AMM in all participants (&#x3b2;&#x2009;=&#x2009;0.049, SE&#x2009;=&#x2009;0.024, p&#x2009;=&#x2009;0.039) and males (&#x3b2;&#x2009;=&#x2009;0.057, SE&#x2009;=&#x2009;0.025, p&#x2009;=&#x2009;0.021), but only marginally significant in females (&#x3b2;&#x2009;=&#x2009;0.043, SE&#x2009;=&#x2009;0.025, p&#x2009;=&#x2009;0.090) based on IVW models was noticed. No significant pleiotropy effects were detected for the IVs in the two-sample MR investigations. In MVMR analysis, a positive causal effect of 25(OH)D on AMM was observed in the total population (&#x3b2;&#x2009;=&#x2009;0.116, SE&#x2009;=&#x2009;0.051, p&#x2009;=&#x2009;0.022), males (&#x3b2;&#x2009;=&#x2009;0.111, SE&#x2009;=&#x2009;0.053, p&#x2009;=&#x2009;0.036) and females (&#x3b2;&#x2009;=&#x2009;0.124, SE&#x2009;=&#x2009;0.054, p&#x2009;=&#x2009;0.021). CONCLUSIONS: Our results suggested a positive causal effect of serum 25(OH)D concentration on AMM; however, more researches are warranted to unveil the underlying biological mechanisms and evaluate the effects of vitamin D intervention on AMM.

Humans↗

Genetic Association Between Sleep Traits and Vertigo Risk: A Two-sample Bidirectional Mendelian Randomization Study.

BACKGROUND: Observational studies suggest the potential association between sleep traits and vertigo; however, causal evidence remains limited. OBJECTIVE: This study aimed to explore the relationship between genetically predicted sleep traits and vertigo with the Mendelian randomization (MR) method. METHODS: Instrumental variables for sleep traits (snoring, sleep duration, insomnia, daytime sleepiness, daytime napping, and chronotype) were adopted from genomewide association studies (GWAS) data of European ancestry from UK Biobank. The summary-level datasets of vertigo were retrieved from the GWAS of FinnGen. Inversevariance weighted (IVW) method was adopted as the main analysis. RESULTS: IVW analysis revealed a significant association between genetically predicted daytime napping (OR = 1.51, 95% CI =1.08-2.12, P = 0.016) and chronotype (OR = 1.13, 95% CI =1.01-1.26, P = 0.033), both of which were associated with an increased risk of vertigo. However, we did not find evidence for a causal effect of snoring, overall sleep duration, long sleep duration, short sleep duration, insomnia, and excessive daytime sleepiness on vertigo. No reverse causality was detected. CONCLUSION: Our findings suggest that abnormal sleep patterns may serve as risk factors for vertigo disorders and offer opportunities for the prevention and management of vertigo disorders.

Humans↗

Exploring correlations between immune cell phenotypes and the risk of epilepsy: A bidirectional Mendelian randomization study.

BACKGROUND: Neuroinflammation plays an important pathophysiological role in epilepsy; however, the precise connection between immune cells and epilepsy remains unclear. This study used Mendelian randomization (MR) to analyze the causal relationship between 731 immune cell traits and epilepsy. METHODS: Based on data from a genome-wide association study (GWAS), a bidirectional two-sample MR analysis was conducted to investigate the potential influence of immune cell phenotypes on epilepsy. Five MR methods were used to analyze the results, with the inverse variance weighted (IVW) method as the primary method, and the results were corrected using the false discovery rate (FDR) method. Sensitivity analyses were performed to test for heterogeneity and horizontal pleiotropy. RESULTS: After correction for FDR, four immune traits remained significantly associated with epilepsy risk: CD25 expression on memory (OR&#xa0;=&#xa0;1.04, 95&#xa0;% CI&#xa0;=&#xa0;1.02&#xa0;&#x223c;&#xa0;1.06,P&#xa0;=&#xa0;2.55&#xa0;&#xd7;&#xa0;10-4), IgD+CD38dim (OR&#xa0;=&#xa0;1.05, 95&#xa0;% CI&#xa0;=&#xa0;1.02&#xa0;&#x223c;&#xa0;1.08, P&#xa0;=&#xa0;4.73&#xa0;&#xd7;&#xa0;10-4), CD24+CD27+ (OR&#xa0;=&#xa0;1.04, 95&#xa0;% CI&#xa0;=&#xa0;1.02&#xa0;&#x223c;&#xa0;1.06, P&#xa0;=&#xa0;4.82&#xa0;&#xd7;&#xa0;10-4), and IgD-CD38dim (OR&#xa0;=&#xa0;1.04, 95&#xa0;% CI&#xa0;=&#xa0;1.02&#xa0;&#x223c;&#xa0;1.06, P&#xa0;=&#xa0;1.04&#xa0;&#xd7;&#xa0;10-3) B cells. The risk of generalized epilepsy was significantly associated with two immune cell traits, whereas that of focal epilepsy was significantly associated with seven immune cell traits. Furthermore, immune cell phenotypes are not affected by genetically predicted epilepsy. CONCLUSION: This MR study affirms the causal connection between circulating immune cells and epilepsy, offering guidance for further understanding of the immune mechanisms that underlie epilepsy and the discovery of novel targets for therapy.

Humans↗

Integration of multiple omics reveals key targets and cellular mechanisms for intervention in sarcopenia.

BACKGROUND: Sarcopenia, an age-related syndrome characterized by progressive loss of muscle mass, strength, and function, presents a significant global health burden with limited therapeutic interventions. This study integrates genomic causality, multi-tissue omics, and cellular mediation analyses to identify and prioritize mechanistically grounded therapeutic targets. METHODS: A multi-tiered analytical framework was applied, beginning with two-sample Mendelian randomization (MR) to infer causal relationships between 4907 plasma proteins (cis-pQTLs from 35,559 individuals) and sarcopenia traits in Pan-UK Biobank participants. Bayesian colocalization and transcriptomic validation in human sarcopenia muscle biopsies were employed to prioritize targets. Cellular mediation analysis quantified contributions of immune and stromal cell subtypes to protein-trait pathways using transcriptomic deconvolution. RESULTS: MR identified 1237 plasma proteins causally associated with sarcopenia traits, with six targets (HGFAC, GATM, HMOX2, F2, LMAN2L, HPGDS) validated through colocalization, transcriptomic expression, and sarcopenia-related dysregulation. Cellular mediation revealed immune mechanisms underlying HGFAC's effects, with CD4+ regulatory T cells mediating 3.49 % of its impact on sarcopenia traits. Prothrombin exhibited muscle-protective effects independent of coagulation. CONCLUSION: This study establishes a causal map linking plasma proteins to sarcopenia through immune-stromal interactions. The integration of MR, multi-omics validation, and cellular mediation prioritizes six proteins as actionable targets, supporting repurposing of thrombin inhibitors and development of immunometabolic therapies. The framework bridges genomic causality with cellular pathophysiology, advancing precision strategies for age-related muscle decline.

Humans↗

Education, socioeconomic status, leisure sedentary behaviors and female infertility: mendelian randomization study.

BACKGROUND: Previous studies have indicated that education, socioeconomic status, and leisure sedentary behavior may be associated with female infertility. However, it remains unclear whether these associations imply causal relationships. METHODS: Genetic variants from genome-wide association studies (GWAS) of education, socioeconomic status, and leisure sedentary behaviors were obtained from the UK Biobank and MRC-IEU database (Medical Research Council Integrative Epidemiology Unit), female infertility data was acquired from the FinnGen Biobank. Univariable and multivariable MR analyses were performed to explore the relationships between these traits and female infertility. RESULTS: The results of the univariate MR analysis indicated that age of full-time education had a protective effect on female infertility (odds ratio [OR] 0.471; 95% confidence interval [CI] 0.24 to 0.93; p&#x2009;=&#x2009;0.03). Multivariable MR and reverse MR studies support the existence of a relationship between them. However, no causal correlation was found between other traits and female infertility. No significant heterogeneity or horizontal pleiotropy was detected, and the stability of the results was confirmed through sensitivity analysis and the leave-one-out test. CONCLUSIONS: A later age of completion of full-time education may be causally related to a reduced risk of female infertility, but no causality is established between other educational levels factors, socioeconomic status, or sedentary behaviors and infertility risk.

Humans↗

The bidirectional genetic causality between immunocyte phenotypes and dilated cardiomyopathy: A bidirectional Mendelian randomization study.

The association between immunocyte phenotypes and dilated cardiomyopathy (DCM) has been explored, however the exact pathogenesis of the relationship between immune cells and DCM is unclear. This bidirectional two-sample Mendelian randomization (MR) research aims to further validate the causal link between 731 immunocyte phenotypes and DCM. Summary statistics from a genome-wide association study data of individuals with European ancestry were utilized, including 1444 DCM cases and 353,937 controls, as well as 3757 European adults for the 731 immunocyte phenotypes. Causal effects were estimated using inverse variance weighted, MR-Egger regression, weight median estimator, weighted mode, and simple mode. Sensitivity analysis was conducted to confirm data robustness and feasibility. Based on the inverse variance weighted findings, 14 immunocyte phenotypes were risk factors for DCM (P&#x2005;<&#x2005;.05, odds ratio [OR]&#x2005;>&#x2005;1), while 15 immunocyte phenotypes exhibited a protective effect on DCM (P&#x2005;<&#x2005;.05, OR&#x2005;<&#x2005;1). The results of reverse MR analysis suggested evidence that DCM occurrence might elevate the levels of 17 immunocyte phenotypes (P&#x2005;<&#x2005;.05, OR&#x2005;>&#x2005;1) and decrease the levels of 9 immunocyte phenotypes (P&#x2005;<&#x2005;.05, OR&#x2005;<&#x2005;1). Our research indicated that CD28 on secreting regulatory T cell could mitigate the occurrence of DCM, and reciprocally, the progression of DCM could reduce the level of CD28 on secreting regulatory T cell. This study confirmed the bidirectional genetic predictive relationship between immunocyte phenotypes and DCM, underscoring the complex interplay between DCM and the immune system.

Cardiomyopathy, Dilated↗

Genetic and phenotypic characterization of capsule mutants of Cryptococcus neoformans.

Stable mutants with reduced capacity to produce capsules were isolated from suspensions of Cryptococcus neoformans after treatment of the wild type with a mutagen. The mutants could be assigned one of two phenotypes, hypocapsular or acapsular. Hypocapsular mutants were immunochemically and physicochemically indistinguishable from the wild type, whereas acapsular mutants lacked a major capsular antigen and a negatively charged exterior. In genetic analysis, the mutant trait segregated as a Mendelian gene (1:1) when random basidiospores from an outcross were studied, and analysis of products of single meiotic events from outcrossed mutants was likewise consistent with meiotic segregation. Two-factor crosses yielded the expected four classes of progeny, with recombinants equal to parentals. We concluded that chromosomal genes are responsible for synthesis of the cryptococcal capsule and that random basidiospore analysis represents a useful technique for genetic analysis in this species.

Antigens, Fungal↗

Uric Acid Levels and Cardiovascular and Cerebrovascular Diseases: A Mendelian Randomization Study.

INTRODUCTION: The relationship between uric acid (UA) levels and cardiovascular and cerebrovascular diseases (CCVD) is controversial. A two-sample Mendelian randomization (MR) study was conducted to explore the causal effects of UA levels on CCVD. METHODS: Genetic variants strongly associated with UA levels were selected as instrumental variables from the Genome-Wide Association Study (GWAS) dataset. The GWAS data, sourced from the Global Urate Genetics Consortium (GUGC), comprised a sample size of 110,347 individuals. The selected CCVD outcomes included stroke, coronary artery disease (CAD), as well as atrial fibrillation and flutter. The primary analytical approach employed the inverse-variance weighted (IVW) method, supplemented by MR-Egger and weighted median as complementary methods. Sensitivity analysis was performed to test heterogeneity and pleiotropy. RESULTS: The MR analysis results indicated a causal association between UA levels and stroke (odds ratio [OR]: 1.002; 95% confidence interval [CI]: 1.000-1.003; p = 0.036), CAD (OR: 1.118; 95% CI: 1.044-1.197; p = 0.001), as well as atrial fibrillation and flutter (OR: 1.141; 95% CI: 1.037-1.256; p = 0.007). The results of MR-Egger and weighted median methods confirmed the direction of the IVW results, enhancing the robustness of the findings. No significant anomalies were detected in the sensitivity analysis. CONCLUSION: The MR study suggests that UA levels exert causal effects on stroke, CAD, as well as atrial fibrillation and flutter.

Humans↗