TATA box-binding protein-related factor 3 drives the mesendoderm specification of human embryonic stem cells by globally interacting with the TATA box of key mesendodermal genes

TAF1 is needed for the proliferation and maturation of thyroid follicle cells via Notch signaling

Thyroid dysgenesis (TD) is the common pathogenic mechanism of congenital hypothyroidism (CH). In addition, known pathogenic genes are limited to those that are directly involved in thyroid development. To identify additional candidate pathogenetic genes, we performed forward genetic screening for TD in zebrafish, followed by positional cloning. The candidate gene was confirmed in vitro using the Nthy-ori 3.1 cell line and in vivo using a zebrafish model organism. We obtained a novel zebrafish line with thyroid dysgenesis and identified the candidate pathogenetic mutation TATA-box binding protein associated Factor 1 (taf1) by positional cloning. Further molecular studies revealed that taf1 was needed for the proliferation of thyroid follicular cells by binding to the NOTCH1 promoter region. Knockdown of TAF1 impaired the proliferation and maturation of thyroid cells, thereby leading to thyroid dysplasia. This study showed that TAF1 promoted Notch signaling and that this association played a pivotal role in thyroid development.NEW & NOTEWORTHY In our study, we obtained a novel zebrafish line with thyroid dysgenesis (TD) and identified the candidate pathogenetic mutation TATA-box binding protein associated Factor 1 (taf1). Further researches revealed that taf1 was required for thyroid follicular cells by binding to the NOTCH1 promoter region. Our findings revealed a novel role of TAF1 in thyroid morphogenesis.

Natural antisense transcription of presenilin in sea urchin reveals a possible role for natural antisense transcription in the general control of gene expression during development

One presenilin gene (PSEN) is expressed in the sea urchin embryo, in the vegetal pole of the gastrula and then mainly in cilia cells located around the digestive system of the pluteus, as we recently have reported. PSEN expression must be accurately regulated for correct execution of these two steps of development. While investigating PSEN expression changes in embryos after expansion of endoderm with LiCl or of ectoderm with Zn2+ by whole-mount in situ hybridization (WISH) and quantitative PCR (qPCR), we detected natural antisense transcription of PSEN. We then found that Endo16 and Wnt5, markers of endo-mesoderm, and of Hnf6 and Gsc, markers of ectoderm, are also sense and antisense transcribed. We discuss that general gene expression could depend on both sense and antisense transcription. This mechanism, together with the PSEN gene, should be included in gene regulatory networks (GRNs) that theorize diverse processes in this species. We suggest that it would also be relevant to investigate natural antisense transcription of PSEN in the field of Alzheimer's disease (AD) where the role of human PSEN1 and PSEN2 is well known.

Integrative Analysis to Identify Genes Associated with Stemness and Immune Infiltration in Glioblastoma

It is imperative to identify the mechanisms that confer stemness to the cancer cells for more effective targeting. Moreover, there are not many studies on the link between stemness characteristics and the immune response in tumours. Therefore, in the current study involving GBM, we started with the study of BIRC5 (one of the rare genes differentially expressed in normal and cancer cells) and CXCR4 (gene involved in the survival and proliferation of CSCs). Together, these genes have not been systematically explored. We used a set of 27 promoter methylated regions in GBM. Our analysis showed that four genes corresponding to these regions, namely EOMES, BDNF, HLA-A, and PECAM1, were involved with BIRC5 and CXCR4. Interestingly, we found EOMES to be very significantly involved in stemness and immunology and it was positively correlated to CXCR4. Additionally, BDNF, which was significant in methylation, was negatively correlated to BIRC5.

Myosin light chain 2 marks differentiating ventricular cardiomyocytes derived from human embryonic stem cells

Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) have great value for studies of human cardiac development, drug discovery, disease modeling, and cell therapy. However, the mixed cardiomyocyte subtypes (ventricular-, atrial-, and nodal-like myocytes) and the maturation heterogeneity of hPSC-CMs restrain their application in vitro and in vivo. Myosin light chain 2 (MYL2, encoding the ventricular/cardiac muscle isoform MLC2v protein) is regarded as a ventricular-specific marker of cardiac myocardium; however, its restricted localization to ventricles during human heart development has been questioned. Consequently, it is currently unclear whether MYL2 definitively marks ventricular hESC-CMs. Here, by using a MYL2-Venus hESC reporter line, we characterized a time-dependent increase of the MYL2-Venus positive (MLC2v-Venus⁺) hESC-CMs during differentiation. We also compared the molecular, cellular, and functional properties between the MLC2v-Venus⁺ and MYL2-Venus negative (MLC2v-Venus^-) hESC-CMs. At early differentiation stages of hESC-CMs, we reported that both MLC2v-Venus^- and MLC2v-Venus⁺ CMs displayed ventricular-like traits but the ventricular-like cells from MLC2v-Venus⁺ hESC-CMs displayed more developed action potential (AP) properties than that from MLC2v-Venus^- hESC-CMs. Meanwhile, about a half MLC2v-Venus^- hESC-CM population displayed atrial-like AP properties, and a half showed ventricular-like AP properties, whereas only ~ 20% of the MLC2v-Venus^- hESC-CMs expressed the atrial marker nuclear receptor subfamily 2 group F member 2 (NR2F2, also named as COUPTFII). At late time points, almost all MLC2v-Venus⁺ hESC-CMs exhibited ventricular-like AP properties. Further analysis demonstrates that the MLC2v-Venus⁺ hESC-CMs had enhanced Ca²⁺ transients upon increase of the MLC2v level during cultivation. Concomitantly, the MLC2v-Venus⁺ hESC-CMs showed more defined sarcomeric structures and better mitochondrial function than those in the MLC2v-Venus^- hESC-CMs. Moreover, the MLC2v-Venus⁺ hESC-CMs were more sensitive to hypoxic stimulus than the MLC2v-Venus^- hESC-CMs. These results provide new insights into the development of human ventricular myocytes and reveal a direct correlation between the expression profile of MLC2v and ventricular hESC-CM development. Our findings that MLC2v is predominantly a ventricular marker in developmentally immature hESC-CMs have implications for human development, drug screening, and disease modeling, and this marker should prove useful in overcoming issues associated with hESC-CM heterogeneity.