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To leverage the advancements in genome-wide association studies (GWAS) and quantitative trait loci (QTL) mapping for traits and molecular phenotypes to gain mechanistic understanding of the genetic regulation, biological researchers often investigate the expression QTLs (eQTLs) that colocalize with QTL or GWAS peaks. Our research is inspired by 2 such studies. One aims to identify the causal single nucleotide polymorphisms that are responsible for the phenotypic variation and whose effects can be explained by their impacts at the transcriptomic level in maize. The other study in mouse focuses on uncovering the cis-driver genes that induce phenotypic changes by regulating trans-regulated genes. Both studies can be formulated as mediation problems with potentially high-dimensional exposures, confounders, and mediators that seek to estimate the overall indirect effect (IE) for each exposure. In this paper, we propose MedDiC, a novel procedure to estimate the overall IE based on difference-in-coefficients approach. Our simulation studies find that MedDiC offers valid inference for the IE with higher power, shorter confidence intervals, and faster computing time than competing methods. We apply MedDiC to the 2 aforementioned motivating datasets and find that MedDiC yields reproducible outputs across the analysis of closely related traits, with results supported by external biological evidence. The code and additional information are available on our GitHub page (https://github.com/QiZhangStat/MedDiC).
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http://dx.doi.org/10.1093/biomtc/ujae050 | DOI Listing |
Bioinformatics
September 2025
Department of Biostatistics, University of Pittsburgh, Pittsburgh, Pennsylvania United States.
Summary: Causal mediation analysis investigates the role of mediators in the relationship between exposure and outcome. In the analysis of omics or imaging data, mediators are often high-dimensional, presenting challenges such as multicollinearity and interpretability. Existing methods either compromise interpretability or fail to effectively prioritize mediators.
View Article and Find Full Text PDFBiomed Environ Sci
August 2025
Precision Key Laboratory of Public Health, School of Public Health, Guangdong Medical University, Dongguan 523808, Guangdong, China;Maternal and Child Research Institute, Shunde Women and Children's Hospital, Guangdong Medical University, Foshan 528300, Guangdong, China.
Objective: Humans are exposed to complex mixtures of environmental chemicals and other factors that can affect their health. Analysis of these mixture exposures presents several key challenges for environmental epidemiology and risk assessment, including high dimensionality, correlated exposure, and subtle individual effects.
Methods: We proposed a novel statistical approach, the generalized functional linear model (GFLM), to analyze the health effects of exposure mixtures.
Dev Psychobiol
September 2025
Department of Psychology, Stanford University, Stanford, California, USA.
Early adversity is a well-established risk factor for psychopathology in youth. Contemporary taxonomies of adversity seek to distill the diverse stressors children face into meaningful categories of experience to enable more precise prediction of risk; however, few studies have tested these models using data-driven approaches in well-characterized, longitudinal samples. Here, we examined the latent structure of early stress across diverse domains of exposure, tested differential associations with psychopathology in adolescence, and investigated frontolimbic functional connectivity as a potential mediator.
View Article and Find Full Text PDFBr J Pharmacol
September 2025
Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia.
Background And Purpose: Patients with amyotrophic lateral sclerosis (ALS) are prescribed many medications for symptomatic relief. However, how potential alterations to the blood-brain barrier (BBB) affect the brain exposure of drugs in ALS remains under-investigated.
Experimental Approach: We used high-dimensional proteomic analysis, cellular metabolism, and mitochondrial functional assays to characterise isolated brain microvascular endothelial cells (BMECs) from wildtype and SOD1 transgenic mice, a mouse model of familial ALS, at a late-symptomatic age (P115-120), together with a transcardiac brain perfusion technique to assess BBB function in situ.
Scand Stat Theory Appl
June 2025
Department of Biostatistics, Columbia University, New York, New York, USA.
It is of substantial scientific interest to detect mediators that lie in the causal pathway from an exposure to a survival outcome. However, with high-dimensional mediators, as often encountered in modern genomic data settings, there is a lack of powerful methods that can provide valid post-selection inference for the identified marginal mediation effect. To resolve this challenge, we develop a post-selection inference procedure for the maximally selected natural indirect effect using a semiparametric efficient influence function approach.
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