Simultaneous Enrichment Analysis of all Possible Gene-sets: Unifying Self-Contained and Competitive Methods
BRIEFINGS IN BIOINFORMATICS
Authors: Ebrahimpoor, Mitra; Spitali, Pietro; Hettne, Kristina; Tsonaka, Roula; Goeman, Jelle
Abstract
Studying sets of genomic features is increasingly popular in genomics, proteomics and metabolomics since analyzing at set level not only creates a natural connection to biological knowledge but also offers more statistical power. Currently, there are two gene-set testing approaches, self-contained and competitive, both of which have their advantages and disadvantages, but neither offers the final solution. We introduce simultaneous enrichment analysis (SEA), a new approach for analysis of feature sets in genomics and other omics based on a new unified null hypothesis, which includes the self-contained and competitive null hypotheses as special cases. We employ closed testing using Simes tests to test this new hypothesis. For every feature set, the proportion of active features is estimated, and a confidence bound is provided. Also, for every unified null hypotheses, a P-value is calculated, which is adjusted for family-wise error rate. SEA does not need to assume that the features are independent. Moreover, users are allowed to choose the feature set(s) of interest after observing the data. We develop a novel pipeline and apply it on RNA-seq data of dystrophin-deficient mdx mice, showcasing the flexibility of the method. Finally, the power properties of the method are evaluated through simulation studies.
Genetic disruption of the inflammasome adaptor ASC has minimal impact on the pathogenesis of Duchenne muscular dystrophy in mdx mice
LIFE SCIENCES
Authors: Lau, Yeh Siang; Zhao, Lixia; Zhang, Chen; Li, Haiwen; Han, Renzhi
Abstract
Aim: Up-regulation of inflammasome proteins was reported in dystrophin-deficient muscles. However, it remains to be determined whether inflammasome activation plays a role in the pathogenesis of Duchenne muscular dystrophy. This study was therefore set out to investigate whether genetic disruption of the inflammasome pathway impacts the disease progression in mdx mice. Main methods: Mice deficient in both dystrophin and ASC (encoded by Pycard [PYD And CARD Domain Containing]) were generated. The impact of ASC deficiency on muscular dystrophy of mdx mice were assessed by measurements of serum cytokines, Western blot, real-time PCR and histopathological staining. Key findings: The pro-inflammatory cytokines such as TNF-alpha, IL-6, KC/GRO and IL-10 were markedly increased in the sera of 8-week-old mdx mice compared to WT. Western blotting showed that P2X7, caspase-1, ASC and IL 18 were upregulated. Disruption of ASC and dystrophin expression in the mdx/ASC(-/-) mice was verified by Western blot analysis. Histopathological analysis did not find significant alterations in the muscular dystrophy phenotype in mdx/ASC(-/-) mice as compared to mdx mice. Significance: Taken together, our results show that disruption of the central adaptor ASC of the inflammasome is insufficient to alleviate muscular dystrophy phenotype in mdx mice.