74 research outputs found
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Cellular deconvolution of GTEx tissues powers discovery of disease and cell-type associated regulatory variants.
The Genotype-Tissue Expression (GTEx) resource has provided insights into the regulatory impact of genetic variation on gene expression across human tissues; however, thus far has not considered how variation acts at the resolution of the different cell types. Here, using gene expression signatures obtained from mouse cell types, we deconvolute bulk RNA-seq samples from 28 GTEx tissues to quantify cellular composition, which reveals striking heterogeneity across these samples. Conducting eQTL analyses for GTEx liver and skin samples using cell composition estimates as interaction terms, we identify thousands of genetic associations that are cell-type-associated. The skin cell-type associated eQTLs colocalize with skin diseases, indicating that variants which influence gene expression in distinct skin cell types play important roles in traits and disease. Our study provides a framework to estimate the cellular composition of GTEx tissues enabling the functional characterization of human genetic variation that impacts gene expression in cell-type-specific manners
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Allele-specific NKX2-5 binding underlies multiple genetic associations with human electrocardiographic traits.
The cardiac transcription factor (TF) gene NKX2-5 has been associated with electrocardiographic (EKG) traits through genome-wide association studies (GWASs), but the extent to which differential binding of NKX2-5 at common regulatory variants contributes to these traits has not yet been studied. We analyzed transcriptomic and epigenomic data from induced pluripotent stem cell-derived cardiomyocytes from seven related individuals, and identified ~2,000 single-nucleotide variants associated with allele-specific effects (ASE-SNVs) on NKX2-5 binding. NKX2-5 ASE-SNVs were enriched for altered TF motifs, for heart-specific expression quantitative trait loci and for EKG GWAS signals. Using fine-mapping combined with epigenomic data from induced pluripotent stem cell-derived cardiomyocytes, we prioritized candidate causal variants for EKG traits, many of which were NKX2-5 ASE-SNVs. Experimentally characterizing two NKX2-5 ASE-SNVs (rs3807989 and rs590041) showed that they modulate the expression of target genes via differential protein binding in cardiac cells, indicating that they are functional variants underlying EKG GWAS signals. Our results show that differential NKX2-5 binding at numerous regulatory variants across the genome contributes to EKG phenotypes
iPSCORE: A Resource of 222 iPSC Lines Enabling Functional Characterization of Genetic Variation across a Variety of Cell Types.
Large-scale collections of induced pluripotent stem cells (iPSCs) could serve as powerful model systems for examining how genetic variation affects biology and disease. Here we describe the iPSCORE resource: a collection of systematically derived and characterized iPSC lines from 222 ethnically diverse individuals that allows for both familial and association-based genetic studies. iPSCORE lines are pluripotent with high genomic integrity (no or low numbers of somatic copy-number variants) as determined using high-throughput RNA-sequencing and genotyping arrays, respectively. Using iPSCs from a family of individuals, we show that iPSC-derived cardiomyocytes demonstrate gene expression patterns that cluster by genetic background, and can be used to examine variants associated with physiological and disease phenotypes. The iPSCORE collection contains representative individuals for risk and non-risk alleles for 95% of SNPs associated with human phenotypes through genome-wide association studies. Our study demonstrates the utility of iPSCORE for examining how genetic variants influence molecular and physiological traits in iPSCs and derived cell lines
Targeting HOX transcription factors in prostate cancer
YesBackground: The HOX genes are a family of transcription factors that help to determine cell and tissue identity
during early development, and which are also over-expressed in a number of malignancies where they have been
shown to promote cell proliferation and survival. The purpose of this study was to evaluate the expression of HOX
genes in prostate cancer and to establish whether prostate cancer cells are sensitive to killing by HXR9, an inhibitor
of HOX function.
Methods: HOX function was inhibited using the HXR9 peptide. HOX gene expression was assessed by RNA
extraction from cells or tissues followed by quantitative PCR, and siRNA was used to block the expression of the
HOX target gene, cFos. In vivo modelling involved a mouse flank tumour induced by inoculation with LNCaP cells.
Results: In this study we show that the expression of HOX genes in prostate tumours is greatly increased with
respect to normal prostate tissue. Targeting the interaction between HOX proteins and their PBX cofactor induces
apoptosis in the prostate cancer derived cell lines PC3, DU145 and LNCaP, through a mechanism that involves a
rapid increase in the expression of cFos, an oncogenic transcription factor. Furthermore, disrupting HOX/PBX
binding using the HXR9 antagonist blocks the growth of LNCaP tumours in a xenograft model over an extended
period.
Conclusion: Many HOX genes are highly over-expressed in prostate cancer, and prostate cancer cells are sensitive
to killing by HXR9 both in vitro and in vivo. The HOX genes are therefore a potential therapeutic target in prostate
cancer.The authors gratefully acknowledge the support of the Prostate Project charity (UK)
Aspects of the ecology of the earthworm Eisenia lucens (Waga 1857) studied in the field and in laboratory culture
This work relates data from field sampling of Eisenia lucens and from laboratory-based culture. Field sampling used soil sorting and vermifuge extraction and took place in beech-dominated forests of southwest Poland. Initial work derived population estimates from four sub-communities of the forest looking for seasonal dynamics and later work employed targeted sampling in summer within rotting wood to obtain live specimens for laboratory culture. A preliminary examination within and below rotten wood during winter was also undertaken. In the laboratory, clitellate earthworms were kept at 20 °C, the substrate changed every 6 months, and the population examined. Cocoons were incubated individually at 15 °C, with number of hatchlings per cocoon and the mass of each determined. Hatchlings were grown at 15 °C in field-collected wood and compared with growth in a 1:1 volume ratio of wood and horse manure. Further hatchlings were fed with horse manure only (at 10 °C) and after 19 weeks, half were transferred to 15 °C. In the field, mature individuals varied significantly (p < 0.01) in biomass between 2 sampling sites where found, with an overall mean density across sites of 4.14 ± 3.53 m with a mean biomass of 2.21 ± 1.93 g m . Numbers in soil varied over the sampling period, with a suggestion that this species moves from mineral soil to organic-rich dead wood as conditions permit. In summer, all life stages were recovered from rotting wood above the mineral soil. Sampling in winter found cocoons in rotting wood below snow. These hatched rapidly (within 2 weeks) when taken to the laboratory. Laboratory culture allowed maintenance of a population for 2 years. Mean cocoon mass was 50.6 mg with a mean of 2.9 hatchlings per cocoon and hatchling mass was inversely proportional to number per cocoon. Growth with 50% horse manure was significantly greater (p < 0.001) than with wood. Increased temperature from 10 to 15 °C brought more significantly (p < 0.05) rapid growth. To culture this species through its life cycle, a natural substrate is needed, but then it is necessary to acclimate the animals to something more easily obtainable. More work is needed from field sampling to fully understand the seasonal dynamics of this species, which utilises different parts of the soil profile throughout the year
Differential inflammatory microRNA and cytokine expression in pulmonary sarcoidosis
Sarcoidosis is a granulomatous disease of unknown etiology. The disease has an important inflammatory and immune component; however, its immunopathogenesis is not completely understood. Recently, the role of microRNAs (miRNAs), the small non-coding RNAs, has attracted attention as both being involved in pathogenesis and serving as disease markers. Accordingly, changes in the expression of some miRNAs have been also associated with different autoimmune pathologies. However, not much is known about the role of miRNAs in sarcoidosis. Therefore, the aim of this study was to compare the level of expression of selected miRNAs in healthy individuals and patients with sarcoidosis. We detected significantly increased level of miR-34a in peripheral blood mononuclear cells isolated from sarcoidosis patients. Moreover, significantly up-regulated levels of interferon (IFN)-γ, IFN-γ inducible protein (IP-10) and vascular endothelial growth factor were detected in sera of patients when compared to healthy subjects. Our results add to a known inflammatory component in sarcoidosis. Changes in the levels of miR-34a may suggest its involvement in the pathology of this disease
mRNA accumulation in the Cajal bodies of the diplotene larch microsporocyte
In microsporocytes of the European larch, we demonstrated the presence of several mRNAs in spherical nuclear bodies. In the nuclei of microsporocytes, we observed up to 12 bodies, ranging from 0.5 to 6 μm in diameter, during the prophase of the first meiotic division. Our previous studies revealed the presence of polyadenylated RNA (poly(A) RNA) in these bodies, but did not confirm the presence of nascent transcripts or splicing factors of the SR family. The lack of these molecules precludes the bodies from being the sites of synthesis and early maturation of primary transcripts (Kołowerzo et al., Protoplasma 236:13–19, 2009). However, the bodies serve as sites for the accumulation of splicing machinery, including the Sm proteins and small nuclear RNAs. Characteristic ultrastructures and the molecular composition of the nuclear bodies, which contain poly(A) RNA, are indicative of Cajal bodies (CBs). Here, we demonstrated the presence of several housekeeping gene transcripts—α-tubulin, pectin methylesterase, peroxidase and catalase, ATPase, and inositol-3-phosphate synthase—in CBs. Additionally, we observed transcripts of the RNA polymerase II subunits RPB2 and RPB10 RNA pol II and the core spliceosome proteins mRNA SmD1, SmD2, and SmE. The co-localization of nascent transcripts and mRNAs indicates that mRNA accumulation/storage, particularly in CBs, occurs in the nucleus of microsporocytes
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