Effects of cigarette smoke components on myocardial differentiation of mouse embryonic stem cells

Bioinformatics Analysis of Hub Genes Involved in Smoke-Induced Hemifacial Microsomia Pathogenesis

OBJECTIVE

Tobacco smoke is a recognized teratogen, which increases the risk for hemifacial microsomia (HFM) of the fetus during maternal pregnancy. The present study aimed to explore potential mechanisms and verify hub genes of HFM associated with smoke and tobacco smoke pollution (TSP) via bioinformatics methods.

METHODS

Hemifacial microsomia and smoke and TSP pathogenic genes were obtained. A protein-protein interactional (PPI) network was constructed. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses and molecular complex detection were performed by Metascape. Finally, we used the cytoHubba plug-in to screen the hub genes.

RESULTS

A total of 43 HFM genes and 50 optimal smoke candidate genes were selected. Functional enrichment analysis largely focused on tissue morphogenesis and development. Two modules were identified from the PPI network, and 10 hub genes were screened out. The genes most relevant to smoke-induced HFM pathogenesis included TP53 , ESR1 , ESR2 , and HNRNPL.

CONCLUSIONS

This study identified some significant hub genes, pathways, and modules of HFM related to smoke by bioinformatics analyses. Our results suggest that the TP53 , ESR1 , ESR2 , and HNRNPL gene subfamilies may have played a major role in HFM induced by smoke and TSP.

circ-CCND1 regulates the CCND1/P53/P21 pathway through sponging miR-138-5p in valve interstitial cells to aggravate aortic valve calcification

To discuss the effect and mechanism of circular-CCND1 (circ-CCND1) on the regulation of calcified aortic valve disease (CAVD). Differentially expressed circRNAs were screened through the GSE155119 data set and biological prediction. Subsequently, the miR-138-5p, CCND1, and circ-CCND1 expression were detected in the non-calcified and calcified aortic valve. Then Pearson correlation analysis was performed to analyze the correlation between the above expression, and dual luciferase and RNA-pull down assays for verifying the target relationship. Porcine aortic valve interstitial cells (AVICs) were isolated and transfected with pcDNA-circ-CCND1, miR-138-5p inhibitor, and miR-138-5p mimics. The alkaline phosphatase (ALP) activity was quantitatively analyzed by ALP staining, and alizarin-red staining was to check the calcium nodules formation. Finally, Western blot was applied to detect the expression of proteins associated with osteogenic differentiation (Runx2, Osterix, OPN) and CCND1/P53/P21 pathway proteins. Circ-CCND1 was highly expressed in calcific aortic valves. After inhibiting circ-CCND1 expression, a significant reduction was shown in ALP activity, the degree of ossification and the formation of calcium nodules in AVICs, and osteogenic differentiation-related protein expression and CCND1/P53/P21 pathway protein expression. By contrast, inhibition of miR-138-5p and circ-CCND1 together promoted the calcification of AVICs and expression of CCND1/P53/P21 pathway proteins. P53 inhibitor (PFT-α) could significantly reduce activation of CCND1/P53/P21 pathway protein expression by circ-CCND1 overexpression. However, P53 activator (Nutlin-3) significantly restored the suppression of the above pathway-related protein expression by downregulation of circ-CCND1. Circ-CCND1 sponges miR-138-5p to regulate CCND1 expression, thereby promoting the calcification of AVICs.

Effect of the phenylpyrrole fungicide fludioxonil on cell proliferation and cardiac differentiation in mouse embryonic stem cells

Fludioxnil is extensively used as a fungicide in agricultural application, but its possible impact on embryonic development is not yet well understood. In this study, the potential effect of fludioxonil on cardiac differentiation was evaluated in mouse embryonic stem cells (mESCs). The water-soluble tetrazolium (WST) and colony formation assays were conducted to confirm the effect of fludioxonil on proliferation of mESCs. The effect of fludioxonil on the ability of mESCs to form mouse embryoid bodies (mEBs) was determined by the hanging drop assay, whereas the ability of cardiomyocyte differentiation in the early stage was evaluated by determining the beating ratio (ratio of the number of contracting cells to the number of attached EBs) of cardiomyocytes. The viability of mESCs was significantly decreased (less than 50 %) at 10^-5 M fludioxonil. Results of the colony formation assay revealed suppressed colony formation at 10^-5 M fludioxonil (about 50 % at 5 days). Furthermore, the expressions of cell-cycle related proteins, i.e., cyclin D1, cyclin E, p21 and p27, were altered and trending towards inhibiting cell growth. Exposure to fludioxonil also resulted in reduced size of the mEB and induced increasing expression levels of the pluripotency markers Oct4, Sox2 and Nanog. Development of the beating ratio in the process of differentiation to cardiomyocytes derived from mESCs was completely inhibited after exposure to 10^-5 M fludioxonil during the early stage of differentiation (day 5), whereas the beating ratio gradually increased after 5-day treatment. Simultaneously, expressions of the cardiomyocyte-related proteins, Gata4, Hand1 and cTnI, were inhibited after exposure to 10^-5 M fludioxonil. Taken together, these results imply that fludioxonil may impact on the developmental process of mESCs, particularly the cardiac lineage.

Melatonin mitigates the adverse effect of hypoxia during myocardial differentiation in mouse embryonic stem cells

Background

Hypoxia causes oxidative stress and affects cardiovascular function and the programming of cardiovascular disease. Melatonin promotes antioxidant enzymes such as superoxide dismutase, glutathione reductase, glutathione peroxidase, and catalase.

Objectives

This study aims to investigate the correlation between melatonin and hypoxia induction in cardiomyocytes differentiation.

Methods

Mouse embryonic stem cells (mESCs) were induced to myocardial differentiation. To demonstrate the influence of melatonin under hypoxia, mESC was pretreated with melatonin and then cultured in hypoxic condition. The cardiac beating ratio of the mESC-derived cardiomyocytes, mRNA and protein expression levels were investigated.

Results

Under hypoxic condition, the mRNA expression of cardiac-lineage markers (Brachyury, Tbx20, and cTn1) and melatonin receptor (Mtnr1a) was reduced. The mRNA expression of cTn1 and the beating ratio of mESCs increased when melatonin was treated simultaneously with hypoxia, compared to when only exposed to hypoxia. Hypoxia-inducible factor (HIF)-1α protein decreased with melatonin treatment under hypoxia, and Mtnr1a mRNA expression increased. When the cells were exposed to hypoxia with melatonin treatment, the protein expressions of phospho-extracellular signal-related kinase (p-ERK) and Bcl-2-associated X proteins (Bax) decreased, however, the levels of phospho-protein kinase B (p-Akt), phosphatidylinositol 3-kinase (PI3K), B-cell lymphoma 2 (Bcl-2) proteins, and antioxidant enzymes including Cu/Zn-SOD, Mn-SOD, and catalase were increased. Competitive melatonin receptor antagonist luzindole blocked the melatonin-induced effects.

Conclusions

This study demonstrates that hypoxia inhibits cardiomyocytes differentiation and melatonin partially mitigates the adverse effect of hypoxia in myocardial differentiation by regulating apoptosis and oxidative stress through the p-AKT and PI3K pathway.

Adverse effects of nicotine on cardiogenic differentiation from human embryonic stem cells detected by single-cell RNA sequencing

Tobacco smoking was one of the important adverse factors for congenital heart disease. The effects of nicotine, the main component of tobacco, on human embryonic cardiogenesis and related mechanisms remain poorly understood. This work used single-cell RNA sequencing to investigate the effects of nicotine on human embryonic stem cell (hESC) line H9 and its underlying mechanisms during cardiac differentiation. H9 was cultured in feeder-free medium and differentiated in cardiac condition medium when cells reached 90% confluent. Cell viability was detected by MTT after different concentration of nicotine treatment. Different expressed genes during cardiac differentiation was analyzed by single-cell RNA sequencing (scRNA-seq). Key gene expressions were confirmed by qPCR and Western blot. Results showed that 0.1μM-10μM nicotine did not affect H9 cell proliferation. Nicotine 1 μM down-regulated cardiac progenitor cell, mesoderm cell, smooth muscle cell and neural crest cell relatively. Snail1/2 regulating endocardial cushion development were downregulated apparently at differention day 6. Nicotine didn't affect bry-1 and mesp-1 but inhibited cardiac transcript factors. Consequently, the expression of cTnI, a marker of cardiomyocytes was decreased significantly. The data suggest direct adverse effects of nicotine on heart development at the single-cell level and offer a new approach for estimate drug and environmental toxicity on the pathogenesis of the embryonic cardiovascular system development.