Project description:Arsenic in inorganic form is a known human carcinogen; even low levels of arsenic can interfere with the endocrine system. In mammalian development, arsenic exposure can cause a malformation of fetuses and be lethal. This study examined the effects of sodium arsenite (SA) as the inorganic form of arsenic in embryonic bodies (EBs) with three germ layers in the developmental stage. This condition is closer to the physiological condition than a 2D cell culture. The SA treatment inhibited EBs from differentiating into cardiomyocytes. A treatment with 1 μM SA delayed the initiation of beating, presenting successful cardiomyocyte differentiation. In particular, mitochondria function analysis showed that SA downregulated the transcription level of the Complex IV gene. SA increased the fission form of mitochondrion identified by the mitochondria number and length. In addition, a treatment with D-penicillamine, an arsenic chelator, restored the beat of EBs against SA, but not mitochondrial dysfunction. These findings suggest that SA is a toxicant that induces mitochondrial damage and interferes with myocardial differentiation and embryogenesis. This study suggests that more awareness of SA exposure during pregnancy is required because even minuscule amounts have irreversible adverse effects on embryogenesis through mitochondria dysfunction.
Project description:Understanding the molecular pathways regulating cardiogenesis is crucial for the early diagnosis of heart diseases and improvement of cardiovascular disease. During normal mammalian cardiac development, collagen and calcium-binding EGF domain-1 (Ccbe1) is expressed in the first and second heart field progenitors as well as in the proepicardium, but its role in early cardiac commitment remains unknown. Here we demonstrate that during mouse embryonic stem cell (ESC) differentiation Ccbe1 is upregulated upon emergence of Isl1- and Nkx2.5- positive cardiac progenitors. Ccbe1 is markedly enriched in Isl1-positive cardiac progenitors isolated from ESCs differentiating in vitro or embryonic hearts developing in vivo. Disruption of Ccbe1 activity by shRNA knockdown or blockade with a neutralizing antibody results in impaired differentiation of embryonic stem cells along the cardiac mesoderm lineage resulting in a decreased expression of mature cardiomyocyte markers. In addition, knockdown of Ccbe1 leads to smaller embryoid bodies. Collectively, our results show that CCBE1 is essential for the commitment of cardiac mesoderm and consequently, for the formation of cardiac myocytes in differentiating mouse ESCs.
Project description:Background and objectivesSIRT1, a histone diacetylase, modify transactivation function of various transcription factor including p53 and NF-κB. p53 and NF-κB is involved in in vitro differentiation of mouse embryonic stem cells (mESC) into mouse embryoid body (mEB). These suggest that SIRT1 might affect in vitro differentiation of mESC into mEB by regulation of p53 and NF-κB.Methods and resultsIn this study we analyzed the effect of SIRT1 in in vitro differentiation of mESC into mEB using wild and SIRT1 knockout mESC. To examine SIRT1-specific gene in mESC, this study conducted microarray-based differential gene expression analysis between wild and SIRT1 knockout mESC. Comparing their gene expression patterns, this study determined a list of genes regulated by SIRT1. cDNA microarray data-set analysis revealed that genes associated with transcription and signal transduction are significantly modified in SIRT1 knockout mESC. cDNA microarray data-set analysis between mESC and EB in wild and SIRT1 showed that SIRT1 inhibits p53 signaling pathway but not affect NF-κB signaling pathway.ConclusionsThis study suggests that SIRT1 modify mESC differentiation by regulation of p53 transcriptional activity.
Project description:AbstractPluripotent stem cells as a promising cell source with unlimited proliferation and differentiation capacity hold great promise for cell-based therapies in regenerative medicine. Establishment of appropriate culture conditions might enable the control of cellular fate decision in cell culture. Transfer of three-dimensional (3D) embryoid bodies to two-dimensional (2D) monolayer culture systems for initiation of cell differentiation and specialization requires an adaptation of cells which can be managed by extracellular matrix (ECM) materials. Here we compare the characteristics of four different cell culture coating materials and their effect on attachment and differentiation of cells spreading from mouse embryonic stem cell (mESC) derived embryoid bodies (EBs) in mesoderm inducing culture conditions. Atomic force microscope (AFM) and scanning electron microscope (SEM) analysis along with Water Contact Angle technique were used to analyze physical properties of ECM materials and to evaluate cellular behavior on surfaces. Cell migration and differentiation were performed initially by using mesoderm inducing culture conditions and then three germ layer specification conditions. We investigated properties of coating materials such as roughness and wettability control cell attachment, migration and differentiation of mESCs. Matrigel-Gelatin combination is suitable for cell attachment and migration of cells spreading from 3D EBs followed by transfer onto coated surfaces. Matrigel-Gelatin coating enhanced differentiation of cells into mesoderm like cells via EMT process. Our data demonstrated that the Matrigel-Gelatin combination as a cell culture coating matrix might serve as a suitable platform to transfer EBs for differentiation and might influence pluripotent stem cell fate decision into mesoderm and further mesoderm derivative cell populations.Graphical abstractSupplementary informationThe online version contains supplementary material available at 10.1007/s10616-022-00529-z.
Project description:With their unique ability to differentiate into all cell types, embryonic stem (ES) cells hold great therapeutic promise. To improve the efficiency of embryoid body (EB)-mediated ES cell differentiation, we studied murine EBs on the basis of their size and found that EBs with an intermediate size (diameter 100-300 microm) are the most proliferative, hold the greatest differentiation potential, and have the lowest rate of cell death. In an attempt to promote the formation of this subpopulation, we surveyed several biocompatible substrates with different surface chemical parameters and identified a strong correlation between hydrophobicity and EB development. Using self-assembled monolayers of various lengths of alkanethiolates on gold substrates, we directly tested this correlation and found that surfaces that exhibit increasing hydrophobicity enrich for the intermediate-size EBs. When this approach was applied to the human ES cell system, similar phenomena were observed. Our data demonstrate that hydrophobic surfaces serve as a platform to deliver uniform EB populations and may significantly improve the efficiency of ES cell differentiation.
Project description:Bisphenol A (BPA) is used heavily in the production of polycarbonate plastics, thermal receipt paper, and epoxies. Ubiquitous exposure to BPA has been linked to obesity, diabetes, and breast and reproductive system cancers. Resistance to chemotherapeutic agents has also been shown in cancer cell models. Here, we investigated BPA's ability to confer resistance to camptothecin (CPT) in mouse embryonic fibroblasts (MEFs). MEFs are sensitive to CPT; however, co-exposure of BPA with CPT improved cell survival. Co-exposure significantly reduced Top1-DNA adducts, decreasing chromosomal aberrations and DNA strand break formation. This decrease occurs despite BPA treatment increasing the protein levels of Top1. By examining chromatin structure after BPA exposure, we determined that widespread compaction and loss of nuclear volume occurs. Therefore, BPA reduced CPT activity by reducing the accessibility of DNA to Top1, inhibiting DNA adduct formation, the generation of toxic DNA strand breaks, and improving cell survival.
Project description:4,4'-(9-Fluorenylidene) diphenol (BPFL, also known as BHPF and fluorene-9-bisphenol) is a novel bisphenol A substitute that is used in the plastics industry as an organic synthesis intermediate and is a potential endocrine disruptor. However, the deleterious effects of BPFL on porcine Sertoli cells (SCs) and the possible underlying mechanisms are still unclear. Chlorogenic acid (CA) is a free radical scavenger in the cellular antioxidant system that prevents oxidative damage and apoptosis. In the present research, we found that BPFL induced impairments in porcine SCs in a dose-dependent manner and that CA protected porcine SCs against BPFL exposure-induced impairments. Cell viability, proliferation and apoptosis assay results revealed that BPFL exposure could inhibit porcine SC proliferation and induce apoptosis, while CA supplementation ameliorated the effects of BPFL. Further analysis revealed that BPFL exposure induced oxidative stress, mitochondrial membrane potential dysfunction and DNA damage accumulation. Transcriptome analysis and further real-time quantitative PCR and Western blot results showed that BPFL exposure induced endoplasmic reticulum stress and apoptosis. Supplementation with CA dramatically ameliorated these phenotypes in BPFL-exposed porcine SCs. Overall, the present research reveals the possible underlying mechanisms by which BPFL exposure induced impairments and CA supplementation protected against these impairments in porcine SCs.
Project description:The pluripotency of embryonic stem cells (ESCs) relies on appropriate responsiveness to developmental cues. Promoter-proximal pausing of RNA polymerase II (Pol II) has been suggested to play a role in keeping genes poised for future activation. To identify the role of Pol II pausing in regulating ESC pluripotency, we have generated mouse ESCs carrying a mutation in the pause-inducing factor SPT5. Genomic studies reveal genome-wide reduction of paused Pol II caused by mutant SPT5 and further identify a tight correlation between pausing-mediated transcription effect and local chromatin environment. Functionally, this pausing-deficient SPT5 disrupts ESC differentiation upon removal of self-renewal signals. Thus, our study uncovers an important role of Pol II pausing in regulating ESC differentiation and suggests a model that Pol II pausing coordinates with epigenetic modification to influence transcription during mESC differentiation.
Project description:BackgroundEmbryonic Sertoli cells (eSCs) play an important role in sex determination and in male gonad development which makes them a very useful cell type for therapeutic applications. However, the deriving mechanism of Sertoli cells has been unclear and challenging to create a large number of quality eSCs. Therefore, this study aimed to create the eSCs induced from mouse embryonic stem (mES) cells by regulating defined factors and to explore the relevant regulatory mechanism.MethodsSix inducing factors, Sry, Sox9, SF1, WT1, GATA4, and Dmrt1, were respectively transduced into mES cells by lentiviral infection according to the experimental design. The test groups were identified by development stage-specific markers, AMH, Emx2, SF1, and FasL, using flow cytometry. Induced eSCs were determined by FasL and AMH biomarkers under immunofluorescence, immunocytochemistry, and flow cytometry. Moreover, the pluripotency markers, gonad development-related markers, epithelial markers and mesenchymal markers in test groups were transcriptionally determined by qPCR.ResultsIn this study, the co-overexpression of all the six factors effectively produced a large population of eSCs from mES cells in 35 days of culturing. These eSCs were capable of forming tubular-like and ring-like structures with functional performance. The results of flow cytometry indicated that the upregulation of GATA4 and WT1 contributed to the growth of somatic cells in the coelomic epithelium regarded as the main progenitor cells of eSCs. Whereas, SF1 facilitated the development of eSC precursor cells, and Sry and Sox9 promoted the determination of male development. Moreover, the overexpression of Dmrt1 was essential for the maintenance of eSCs and some of their specific surface biomarkers such as FasL. The cellular morphology, biomarker identification, and transcriptomic analysis aided in exploring the regulatory mechanism of deriving eSCs from mES cells.ConclusionConclusively, we have elucidated a differentiation roadmap of eSCs derived from mES cells with a relevant regulatory mechanism. Through co-overexpression of all these six factors, a large population of eSCs was successfully induced occupying 24% of the whole cell population (1 × 105 cells/cm2). By adopting this approach, a mass of embryonic Sertoli cells can be generated for the purpose of co-culture technique, organ transplantation, gonadal developmental and sex determination researches.