scholarly journals A Robust Approach to Identifying Tissue-Specific Gene Expression Regulatory Variants Using Personalized Human Induced Pluripotent Stem Cells

PLoS Genetics ◽  
2009 ◽  
Vol 5 (11) ◽  
pp. e1000718 ◽  
Author(s):  
Je-Hyuk Lee ◽  
In-Hyun Park ◽  
Yuan Gao ◽  
Jin Billy Li ◽  
Zhe Li ◽  
...  
2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Feikun Yang ◽  
Dean W. Richardson

The tendon is highly prone to injury, overuse, or age-related degeneration in both humans and horses. Natural healing of injured tendon is poor, and cell-based therapeutic treatment is still a significant clinical challenge. In this study, we extensively investigated the expression of tenogenic genes in equine bone marrow mesenchymal stem cells (BMSCs) and tenocyte-derived induced pluripotent stem cells (teno-iPSCs) stimulated by growth factors (TGF-β3 and BMP12) combined with ectopic expression of tenogenic transcription factor MKX or cyclic uniaxial mechanical stretch. Western blotting revealed that TGF-β3 and BMP12 increased the expression of transcription factors SCX and MKX in both cells, but the tenocyte marker tenomodulin (TNMD) was detected only in BMSCs and upregulated by either inducer. On the other hand, quantitative real-time PCR showed that TGF-β3 increased the expression of EGR1, COL1A2, FMOD, and TNC in BMSCs and SCX, COL1A2, DCN, FMOD, and TNC in teno-iPSCs. BMP12 treatment elevated SCX, MKX, DCN, FMOD, and TNC in teno-iPSCs. Overexpression of MKX increased SCX, DCN, FMOD, and TNC in BMSCs and EGR1, COL1A2, DCN, FMOD, and TNC in teno-iPSCs; TGF-β3 further enhanced TNC in BMSCs. Moreover, mechanical stretch increased SCX, EGR1, DCN, ELN, and TNC in BMSCs and SCX, MKX, EGR1, COL1A2, DCN, FMOD, and TNC in teno-iPSCs; TGF-β3 tended to further elevate SCX, ELN, and TNC in BMSCs and SCX, MKX, COL1A2, DCN, and TNC in teno-iPSCs, while BMP12 further uptrended the expression of SCX and DCN in BMSCs and DCN in teno-iPSCs. Additionally, the aforementioned tenogenic inducers also affected the expression of signaling regulators SMAD7, ETV4, and SIRT1 in BMSCs and teno-iPSCs. Taken together, our data demonstrate that, in respect to the tenocyte-lineage-specific gene expression, BMSCs and teno-iPSCs respond differently to the tenogenic stimuli, which may affect the outcome of their application in tendon repair or regeneration.


2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Mingtao Zhao ◽  
Shiqiao Ye ◽  
Joe Zhang ◽  
Ningyi Shao ◽  
Chun Liu ◽  
...  

Pathogenic variants in NOTCH1 have been implicated in multiple types of congenital heart defects, such as bicuspid aortic valve, Tetralogy of Fallot, and hypoplastic left heart syndrome (HLHS). However, the mechanisms by which NOTCH1 pathogenic variants cause abnormalities in human embryonic heart development are largely unknown. Here, we used CRISPR/Cas9-mediated genome editing to genetically delete NOTCH1 in human induced pluripotent stem cells (iPSCs). We found that NOTCH1 was dispensable for mesodermal and vascular endothelial differentiation of human iPSCs. Disruption of NOTCH activity promoted venous-specific gene expression but suppressed arterial-specific gene expression in iPSC-derived endothelial cells (iPSC-ECs). Intriguingly, NOTCH1 deletion significantly impaired the cardiac differentiation efficiency. In NOTCH1 homozygous knockout ( NOTCH1 -/- ) iPSC-derived cardiomyocytes (iPSC-CMs), atrial-specific genes ( NR2F2, KCNJ3 , and MYL7 ) were upregulated whereas ventricular-specific genes ( MYL2, IRX4 , and MYH7 ) were downregulated. Electrophysiological analysis by patch clamp and optical mapping indicated that atrial-like cardiomyocytes were dominant whereas the percentage of ventricular-like iPSC-CMs was dramatically reduced (<1%) in NOTCH1 -/- iPSC-CMs. In addition, mitochondrial respiration was reduced in NOTCH1 deficient iPSC-CMs compared to wild-type controls, which was likely attributed to the reduction of ventricular cardiomyocytes in NOTCH1 -/- iPSC-CMs. As NOTCH1 is primarily expressed in endothelial cells rather than cardiomyocytes, we conclude that NOTCH1 affects ventricular cardiomyocyte lineage commitment possibly through controlling cell fate determination of cardiac progenitors during human iPSC differentiation. Our study may provide novel insights into the mechanisms by which NOTCH1 mutations lead to left ventricular hypoplasia in HLHS patients.


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.


2015 ◽  
Vol 20 (5) ◽  
pp. 367-381 ◽  
Author(s):  
Daiki Nukaya ◽  
Kohtaro Minami ◽  
Ritsuko Hoshikawa ◽  
Norihide Yokoi ◽  
Susumu Seino

2020 ◽  
pp. jmedgenet-2019-106608
Author(s):  
Xiaoliang Li ◽  
Guocheng Shi ◽  
Yang Li ◽  
Xiaoqing Zhang ◽  
Ying Xiang ◽  
...  

IntroductionCNV is a vital pathogenic factor of congenital heart disease (CHD). However, few CNVs have been reported for total anomalous pulmonary venous connection (TAPVC), which is a rare form of CHD. Using case-control study, we identified 15q11.2 deletion associated with TAPVC. We then used a TAPVC trio as model to reveal possible molecular basis of 15q11.2 microdeletion.MethodsCNVplex and Chromosomal Microarray were used to identify and validate CNVs in samples from 231 TAPVC cases and 200 healthy controls from Shanghai Children’s Medical Center. In vitro cardiomyocyte differentiation of induced pluripotent stem cells from peripheral blood mononuclear cells for a TAPVC trio with paternal inherited 15q11.2 deletion was performed to characterise the effect of the deletion on cardiomyocyte differentiation and gene expression.ResultsThe 15q11.2 microdeletion was significantly enriched in patients with TAPVC compared with healthy control (13/231 in patients vs 0/200 in controls, p=5.872×10−2, Bonferroni adjusted) using Fisher’s exact test. Induced pluripotent stem cells from the proband could not differentiate into normal cardiomyocyte. Transcriptomic analysis identified a number of differentially expressed genes in the 15q11.2 deletion carriers of the family. TAPVC disease-causing genes such as PITX2, NKX2-5 and ANKRD1 showed significantly higher expression in the proband compared with her healthy mother. Knockdown of TUBGCP5 could lead to abnormal cardiomyocyte differentiation.ConclusionWe discovered that the 15q11.2 deletion is significantly associated with TAPVC. Gene expression profile that might arise from 15q11.2 deletion for a TAPVC family was characterised using cell experiments.


2020 ◽  
Author(s):  
Katherine A. Wood ◽  
Charlie F. Rowlands ◽  
Huw B. Thomas ◽  
Steven Woods ◽  
Julieta O’Flaherty ◽  
...  

ABSTRACTThe craniofacial developmental disorder Burn-McKeown Syndrome (BMKS) is caused by biallelic variants in the pre-messenger RNA splicing factor gene TXNL4A/DIB1. The majority of affected individuals with BMKS have a 34 base pair deletion in the promoter region of one allele of TXNL4A combined with a loss-of-function variant on the other allele, resulting in reduced TXNL4A expression. However, it is unclear how reduced expression of this ubiquitously expressed spliceosome protein results in craniofacial defects during development. Here we reprogrammed peripheral mononuclear blood cells from a BMKS patient and her unaffected mother into induced pluripotent stem cells (iPSCs) and differentiated the iPSCs into induced neural crest cells (iNCCs), the key cell type required for correct craniofacial development. BMKS patient-derived iPSCs proliferated more slowly than both mother- and unrelated control-derived iPSCs, and RNA-Seq analysis revealed significant differences in gene expression and alternative splicing. Patient iPSCs displayed defective differentiation into iNCCs compared to maternal and unrelated control iPSCs, in particular a delay in undergoing an epithelial-to-mesenchymal transition (EMT). RNA-Seq analysis of differentiated iNCCs revealed widespread gene expression changes and mis-splicing in genes relevant to craniofacial and embryonic development that highlight a dampened response to WNT signalling, the key pathway activated during iNCC differentiation. Furthermore, we identified the mis-splicing of TCF7L2 exon 4, a key gene in the WNT pathway, as a potential cause of the downregulated WNT response in patient cells. Additionally, mis-spliced genes shared common sequence properties such as length, splice site strengths and sequence motifs, suggesting that splicing of particular subsets of genes is particularly sensitive to changes in TXNL4A expression. Together, these data provide the first insight into how reduced TXNL4A expression in BMKS patients might compromise splicing and NCC function, resulting in defective craniofacial development in the embryo.


2020 ◽  
Vol In Press (In Press) ◽  
Author(s):  
Alice Sabet ◽  
Negar Azarpira ◽  
Saeid Ghavami ◽  
Leila Kohan

Background: Autophagy is a vital cell survival mechanism that authorizes cells to assort to metabolic stress and is essential for the development and maintenance of cellular and tissue homeostasis, as well as the prevention of human disease. It has also been shown that autophagy plays a significant role in the development and differentiation of stem cells, as well as induced pluripotent stem cells (iPSCs). Objectives: The present study aimed to examine the mRNA expression of the ATG5 gene, one of the key markers of autophagy in human iPSCs (hiPSCs) during endoderm induction. Methods: In this study, we cultured the human iPSC line (R1-hiPSC1) on mitomycin-C, inactivated mouse embryonic fibroblasts (MEF) layer, and used hanging drop protocol to generate embryoid body (EB) and expose differentiation. The Real-time PCR method was used to examine the mRNA expression level of ATG5 in hiPSC during endoderm induction. Results: Our results demonstrated the high mRNA expression of ATG5 in the MEI stage, which shows the high rate of autophagy in MEI days rather than the other stages of differentiation. Conclusions: The modification of ATG5 gene expression within hiPSC during endoderm induction shows the importance of autophagy assessments in hiPSC differentiation. Therefore, subsequent studies are needed to clarify the details of autophagy effects on hiPSC differentiation.


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