scholarly journals Single cell eQTL analysis identifies cell type-specific genetic control of gene expression in fibroblasts and reprogrammed induced pluripotent stem cells

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Drew Neavin ◽  
Quan Nguyen ◽  
Maciej S. Daniszewski ◽  
Helena H. Liang ◽  
Han Sheng Chiu ◽  
...  

Abstract Background The discovery that somatic cells can be reprogrammed to induced pluripotent stem cells (iPSCs) has provided a foundation for in vitro human disease modelling, drug development and population genetics studies. Gene expression plays a critical role in complex disease risk and therapeutic response. However, while the genetic background of reprogrammed cell lines has been shown to strongly influence gene expression, the effect has not been evaluated at the level of individual cells which would provide significant resolution. By integrating single cell RNA-sequencing (scRNA-seq) and population genetics, we apply a framework in which to evaluate cell type-specific effects of genetic variation on gene expression. Results Here, we perform scRNA-seq on 64,018 fibroblasts from 79 donors and map expression quantitative trait loci (eQTLs) at the level of individual cell types. We demonstrate that the majority of eQTLs detected in fibroblasts are specific to an individual cell subtype. To address if the allelic effects on gene expression are maintained following cell reprogramming, we generate scRNA-seq data in 19,967 iPSCs from 31 reprogramed donor lines. We again identify highly cell type-specific eQTLs in iPSCs and show that the eQTLs in fibroblasts almost entirely disappear during reprogramming. Conclusions This work provides an atlas of how genetic variation influences gene expression across cell subtypes and provides evidence for patterns of genetic architecture that lead to cell type-specific eQTL effects.

Author(s):  
Drew Neavin ◽  
Quan Nguyen ◽  
Maciej S. Daniszewski ◽  
Helena H. Liang ◽  
Han Sheng Chiu ◽  
...  

AbstractThe discovery that somatic cells can be reprogrammed to induced pluripotent stem cells (iPSCs) - cells that can be differentiated into any cell type of the three germ layers - has provided a foundation for in vitro human disease modelling1,2, drug development1,2, and population genetics studies3,4. In the majority of instances, the expression levels of genes, plays a critical role in contributing to disease risk, or the ability to identify therapeutic targets. However, while the effect of the genetic background of cell lines has been shown to strongly influence gene expression, the effect has not been evaluated at the level of individual cells. Differences in the effect of genetic variation on the gene expression of different cell-types, would provide significant resolution for in vitro research using preprogramed cells. By bringing together single cell RNA sequencing15–21 and population genetics, we now have a framework in which to evaluate the cell-types specific effects of genetic variation on gene expression. Here, we performed single cell RNA-sequencing on 64,018 fibroblasts from 79 donors and we mapped expression quantitative trait loci (eQTL) at the level of individual cell types. We demonstrate that the large majority of eQTL detected in fibroblasts are specific to an individual sub-type of cells. To address if the allelic effects on gene expression are dynamic across cell reprogramming, we generated scRNA-seq data in 19,967 iPSCs from 31 reprogramed donor lines. We again identify highly cell type specific eQTL in iPSCs, and show that that the eQTL in fibroblasts are almost entirely disappear during reprogramming. This work provides an atlas of how genetic variation influences gene expression across cell subtypes, and provided evidence for patterns of genetic architecture that lead to cell-types specific eQTL effects.


2018 ◽  
Author(s):  
Abhishek K. Sarkar ◽  
Po-Yuan Tung ◽  
John D. Blischak ◽  
Jonathan E. Burnett ◽  
Yang I. Li ◽  
...  

AbstractQuantification of gene expression levels at the single cell level has revealed that gene expression can vary substantially even across a population of homogeneous cells. However, it is currently unclear what genomic features control variation in gene expression levels, and whether common genetic variants may impact gene expression variation. Here, we take a genome-wide approach to identify expression variance quantitative trait loci (vQTLs). To this end, we generated single cell RNA-seq (scRNA-seq) data from induced pluripotent stem cells (iPSCs) derived from 53 Yoruba individuals. We collected data for a median of 95 cells per individual and a total of 5,447 single cells, and identified 241 mean expression QTLs (eQTLs) at 10% FDR, of which 82% replicate in bulk RNA-seq data from the same individuals. We further identified 14 vQTLs at 10% FDR, but demonstrate that these can also be explained as effects on mean expression. Our study suggests that dispersion QTLs (dQTLs) which could alter the variance of expression independently of the mean can have larger fold changes, but explain less phenotypic variance than eQTLs. We estimate 424 individuals as a lower bound to achieve 80% power to detect the strongest dQTLs in iPSCs. These results will guide the design of future studies on understanding the genetic control of gene expression variance.Author summaryCommon genetic variation can alter the level of average gene expression in human tissues, and through changes in gene expression have downstream consequences on cell function, human development, and human disease. However, human tissues are composed of many cells, each with its own level of gene expression. With advances in single cell sequencing technologies, we can now go beyond simply measuring the average level of gene expression in a tissue sample and directly measure cell-to-cell variance in gene expression. We hypothesized that genetic variation could also alter gene expression variance, potentially revealing new insights into human development and disease. To test this hypothesis, we used single cell RNA sequencing to directly measure gene expression variance in multiple individuals, and then associated the gene expression variance with genetic variation in those same individuals. Our results suggest that effects on gene expression variance are smaller than effects on mean expression, relative to how much the phenotypes vary between individuals, and will require much larger studies than previously thought to detect.


2017 ◽  
Vol 20 (4) ◽  
pp. 533-546.e7 ◽  
Author(s):  
Christopher DeBoever ◽  
He Li ◽  
David Jakubosky ◽  
Paola Benaglio ◽  
Joaquin Reyna ◽  
...  

2015 ◽  
Vol 4 (5) ◽  
pp. 886-898 ◽  
Author(s):  
Benjamin Dannenmann ◽  
Simon Lehle ◽  
Dominic G. Hildebrand ◽  
Ayline Kübler ◽  
Paula Grondona ◽  
...  

2020 ◽  
Vol 46 (Supplement_1) ◽  
pp. S234-S234
Author(s):  
Lorna Farrelly ◽  
Shuangping Zhang ◽  
Erin Flaherty ◽  
Aaron Topol ◽  
Nadine Schrode ◽  
...  

Abstract Background Schizophrenia (SCZ) is a severe psychiatric disorder affecting ~1% of the world’s population. It is largely heritable with genetic risk reflected by a combination of common variants of small effect and highly penetrant rare mutations. Chromatin modifications are known to play critical roles in the mediation of many neurodevelopmental processes, and, when disturbed, may also contribute to the precipitation of psychiatric disorders, such as SCZ. While a handful of candidate-based studies have measured changes in promoter-bound histone modifications, few mechanistic studies have been carried out to explore how these modifications may affect chromatin to precipitate behavioral phenotypes associated with the disease. Methods We applied an unbiased proteomics approach to evaluate the epigenetic landscape of SCZ in human induced pluripotent stem cells (hiPSC), neural progenitor cells (NPCs) and neurons from SCZ patients vs. matched controls. We utilized proteomics-based, label free liquid chromatography mass spectrometry (LC-MS/MS) on purified histones from these cells and confirmed our results by western blotting in postmortem SCZ cortical brain tissues. Furthermore we validated our findings with the application of histone interaction assays and structural and biophysical assessments to identify and confirm novel chromatin ‘readers’. To relate our findings to a SCZ phenotype we used a SCZ rodent model of prepulse inhibition (PPI) to perform pharmacological manipulations and behavioral assessments. Results Using label free mass spectrometry we performed PTM screening of hiPSCs, NPCs and matured neurons derived from SCZ patients and matched controls. We identified, amongst others, altered patterns of hyperacetylation in SCZ neurons. Additionally we identified enhanced binding of particular acetylation ‘reader’ proteins. Pharmacological inhibition of such proteins in an animal model of amphetamine sensitization ameliorated PPI deficits further validating this epigenetic signature in SCZ. Discussion Recent evidence indicates that relevance and patterns of acetylation in epigenetics advances beyond its role in transcription and small molecule inhibitors of these aberrant interactions hold promise as useful therapeutics. This study identifies a role for modulating gene expression changes associated with a SCZ epigenetic signature and warrants further investigation in terms of how this early gene expression pattern perhaps determines susceptibility or severity of the SCZ disease trajectory.


PLoS ONE ◽  
2018 ◽  
Vol 13 (10) ◽  
pp. e0205883 ◽  
Author(s):  
Joseph C. Mays ◽  
Michael C. Kelly ◽  
Steven L. Coon ◽  
Lynne Holtzclaw ◽  
Martin F. Rath ◽  
...  

2020 ◽  
Author(s):  
A Andrianto ◽  
Adityo Basworo ◽  
Ivana Purnama Dewi ◽  
Budi Susetio Pikir

IntroductionIt is possible to induce pluripotent stem cells from somatic cells, offering an infinite cell resource with the potential for disease research and use in regenerative medicine. Due to ease of accessibility, minimum invasive treatment, and can be kept frozen, peripheral blood mononuclear cells (PBMC) were an attractive source cell. VC6TFZ, a small molecule compound, has been successfully reprogrammed from mouse fibroblast induced pluripotent stem cells (iPSCs). However, it has not been confirmed in humans.ObjectiveThe aim of this research is to determine whether the small molecule compound VC6TFZ can induced pluripotency of PBMC to generate iPSCs detected with expression of SSEA4 and TRA1-60.MethodsUsing the centrifugation gradient density process, mononuclear cells were separated from peripheral venous blood. Mononuclear cells were cultured for 6 days in the expansion medium. The cells were divided into four groups; group 1 (P1), which was not exposed to small molecules (control group) and groups 2-4 (P2-P4), the experimental groups, subjected to various dosages of the small molecule compound VC6TFZ (VPA, CHIR, Tranylcypromine, FSK, Dznep, and TTNPB). The induction of pluripotency using small molecule compound VC6TFZ was completed within 14 days, then for 7 days the medium shifted to 2i medium. iPSCs identification in based on colony morphology and pluripotent gene expression, SSEA4 and TRA1-60 marker, using immunocytochemistry.ResultsColonies appeared on reprogramming process in day 7th. These colonies had round, large, and cobble stone morphology like ESC. Gene expression of SSEA4 and TRA 1-60 increased statisticaly significant than control group (SSEA4 were P2 p=0.007; P3 p=0.001; P4 p=0.009 and TRA 1-60 were P2 p=0.002; P3 p=0.001; P4 p=0.001).ConclusionSmall molecule compound VC6TFZ could induced pluripotency of human PBMC to generate iPSCs. Pluripotxency marker gene expression, SSEA 4 and TRA 1-60, in the experimental group was statistically significantly higher than in the control group.


Sign in / Sign up

Export Citation Format

Share Document