Endogenous retroviruses (ERVs) are the remnants of retroviral germline infections and are highly abundant in the genomes of vertebrates. At one time considered to be nothing more than inert \'junk\' within genomes, ERVs have been tolerated within host genomes over vast timescales, and their study continues to reveal complex co-evolutionary histories within their respective host species. For example, multiple instances have been characterized of ERVs having been \'borrowed\' for normal physiology, from single copies to ones involved in various regulatory networks such as innate immunity and during early development. Within the cell, the accessibility of ERVs is normally tightly controlled by epigenetic mechanisms such as DNA methylation or histone modifications. However, these silencing mechanisms of ERVs are reversible, and epigenetic alterations to the chromatin landscape can thus lead to their aberrant expression, as is observed in abnormal cellular environments such as in tumors. In this review, we focus on ERV transcriptional control and draw parallels and distinctions concerning the loss of regulation in disease, as well as their precise regulation in early development.

Transposable elements (TEs) comprise a substantial portion of the mammalian genome, with potential implications for both embryonic development and cancer. This study aimed to characterize the expression profiles of TEs in embryonic stem cells (ESCs), cancer cell lines, tumor tissues, and the tumor microenvironment (TME). We observed similarities in TE expression profiles between cancer cells and ESCs, suggesting potential parallels in regulatory mechanisms. Notably, four TE RNAs (HERVH, LTR7, HERV-Fc1, HERV-Fc2) exhibited significant downregulation across cancer cell lines and tumor tissues compared to ESCs, highlighting potential roles in pluripotency regulation. The strong up-regulation of the latter two TEs (HERV-Fc1, HERV-Fc2) in ESCs has not been previously demonstrated and may be a first indication of their role in the regulation of pluripotency. Conversely, tandemly repeated sequences (MSR1, CER, ALR) showed up-regulation in cancer contexts. Moreover, a difference in TE expression was observed between the TME and the tumor bulk transcriptome, with distinct dysregulated TE profiles. Some TME-specific TEs were absent in normal tissues, predominantly belonging to LTR and L1 retrotransposon families. These findings not only shed light on the regulatory roles of TEs in both embryonic development and cancer but also suggest novel targets for anti-cancer therapy. Understanding the interplay between cancer cells and the TME at the TE level may pave the way for further research into therapeutic interventions.

Embryonic stem cells (ESCs) have proven to be a great in vitro model that faithfully recapitulates the events that occur during in vivo embryogenesis, making them a unique tool to study the cellular and molecular mechanisms that define tissue specification during embryonic development. Livestock ESCs are particularly attractive and have broad prospects including drug selection and human disease modeling, improvement of reproductive biotechniques and agriculture-related applications such as production of genetically modified animals. While mice and human ESCs have been established many years ago, no significant advances were made in livestock species until recently. Nowadays, livestock ESCs are available from cattle, pigs, sheep, horses and rabbits with different states of pluripotency. In this review, we summarize the current advances on livestock ESCs establishment and maintenance along with their present and future applications.

BACKGROUND: The establishment of stable porcine embryonic stem cells (pESCs) can contribute to basic and biomedical research, including comparative developmental biology, as well as assessing the safety of stem cell-based therapies. Despite these advantages, most pESCs obtained from in vitro blastocysts require complex media and feeder layers, making routine use, genetic modification, and differentiation into specific cell types difficult. We aimed to establish pESCs with a single cell-passage ability, high proliferative potency, and stable in long-term culture from in vitro-derived blastocysts using a simplified serum-free medium.
METHODS: We evaluated the establishment efficiency of pESCs from in vitro blastocysts using various basal media (DMEM/F10 (1:1), DMEM/F12, and a-MEM) and factors (FGF2, IWR-1, CHIR99021, and WH-4-023). The pluripotency and self-renewal capacity of the established pESCs were analyzed under feeder or feeder-free conditions. Ultimately, we developed a simplified culture medium (FIW) composed of FGF2, IWR-1, and WH-4-023 under serum-free conditions.
RESULTS: The pESC-FIW lines were capable of single-cell passaging with short cell doubling times and expressed the pluripotency markers POU5F1, SOX2, and NANOG, as well as cell surface markers SSEA1, SSEA4, and TRA-1-60. pESC-FIW showed a stable proliferation rate and normal karyotype, even after 50 passages. Transcriptome analysis revealed that pESC-FIW were similar to reported pESC maintained in complex media and showed gastrulating epiblast cell characteristics. pESC-FIW were maintained for multiple passages under feeder-free conditions on fibronectin-coated plates using mTeSR™, a commercial medium used for feeder-free culture, exhibiting characteristics similar to those observed under feeder conditions.
CONCLUSIONS: These results indicated that inhibition of WNT and SRC was sufficient to establish pESCs capable of single-cell passaging and feeder-free expansion under serum-free conditions. The easy maintenance of pESCs facilitates their application in gene editing technology for agriculture and biomedicine, as well as lineage commitment studies.

Cell fate determination is an intricate process which is orchestrated by multiple regulatory layers including signal pathways, transcriptional factors, epigenetic modifications, and metabolic rewiring. Among the sophisticated epigenetic modulations, the repressive mark H3K27me3, deposited by PRC2 (polycomb repressive complex 2) and removed by demethylase KDM6, plays a pivotal role in mediating the cellular identity transition through its dynamic and precise alterations. Herein, we overview and discuss how H3K27me3 and its modifiers regulate pluripotency maintenance and early lineage differentiation. We primarily highlight the following four aspects: 1) the two subcomplexes PRC2.1 and PRC2.2 and the distribution of genomic H3K27 methylation; 2) PRC2 as a critical regulator in pluripotency maintenance and exit; 3) the emerging role of the eraser KDM6 in early differentiation; 4) newly identified additional factors influencing H3K27me3. We present a comprehensive insight into the molecular principles of the dynamic regulation of H3K27me3, as well as how this epigenetic mark participates in pluripotent stem cell-centered cell fate determination.

Mammalian embryos are very vulnerable to environmental toxicants (ETs) exposure. Bisphenol A (BPA), one of the most diffused ETs, exerts endocrine-disrupting effects through estro-gen-mimicking and hormone-like properties, with detrimental health effects, including on reproduction. However, its impact during the peri-implantation stages is still unclear. This study, using gastruloids as a 3D stem cell-based in vitro model of embryonic development, showed that BPA exposure arrests their axial elongation when present during the Wnt/β-catenin pathway activation period by β-catenin protein reduction. Gastruloid reshaping might have been impeded by the downregulation of Snail, Slug and Twist, known to suppress E-cadherin expression and to activate the N-cadherin gene, and by the low expression of the N-cadherin protein. Also, the lack of gastruloids elongation might be related to altered exit of BPA-exposed cells from the pluripotency condition and their following differentiation. In conclusion, here we show that the inhibition of gastruloids\' axial elongation by BPA might be the result of the concomitant Wnt/β-catenin perturbation, reduced N-cadherin expression and Oct4, T/Bra and Cdx2 altered patter expression, which all together concur in the impaired development of mouse gastruloids.

OBJECTIVE: This study aimed to investigate the effect of acoustic vibration on the pluripotency of human embryonic stem cells (hESCs) and evaluate cell proliferation and self-renewal ability post-treatment.
METHODS: The human ES cell line H1 was used for the experiments. hESCs were treated with an acoustic vibration device. Their proliferative ability was subsequently detected using a colony formation assay, while the expression of pluripotency-related markers was detected via immunofluorescence staining. Finally, changes in gene expression levels were examined using quantitative polymerase chain reaction (qPCR) in the presence of appropriate primers.
RESULTS: Compared with normal cells in the control group, the morphology of experimental cells subjected to acoustic vibration did not significantly change. Contrastingly, the colony-forming efficiency of the experimental cells significantly increased. Immunofluorescence staining results showed the cells in experimental group were positive for the pluripotency markers NANOG, octamer-binding transcription factor 4 gene (OCT4), and SRY (sex determining region Y)-box 2 (SOX2). In addition, the expression levels of pluripotency genes NANOG, OCT4, SOX2, and Yes-associated protein (YAP)-related genes were up-regulated following acoustic vibration.
CONCLUSIONS: Our results revealed that acoustic vibration enhanced the proliferative ability of hESCs and increased the expression levels of NANOG, OCT4, SOX2, and YAP-related genes, indicating that acoustic vibration can optimize the self-renewal ability of hESCs and that the YAP signaling pathway may play a critical role in the functional process of acoustic vibration.

In this review, we consider the multipotency of neural crest cells (NCCs), Schwann cell precursors (SCPs), and their role in embryogenesis base on genetic tracing and knock out model animals and single cell transcriptomic analysis. In particular, we summarize and analyze data on the contribution of NCCs and SCPs to the gland development and functions.

Understanding the regulation of human embryonic stem cells (hESCs) pluripotency is critical to advance the field of developmental biology and regenerative medicine. Despite the recent progress, molecular events regulating hESC pluripotency, especially the transition between naive and primed states, still remain unclear. Here we show that naive hESCs display lower levels of O-linked N-acetylglucosamine (O-GlcNAcylation) than primed hESCs. O-GlcNAcase (OGA), the key enzyme catalyzing the removal of O-GlcNAc from proteins, is highly expressed in naive hESCs and is important for naive pluripotency. Depletion of OGA accelerates naive-to-primed pluripotency transition. OGA is transcriptionally regulated by EP300 and acts as a transcription regulator of genes important for maintaining naive pluripotency. Moreover, we profile protein O-GlcNAcylation of the two pluripotency states by quantitative proteomics. Together, this study identifies OGA as an important factor of naive pluripotency in hESCs and suggests that O-GlcNAcylation has a broad effect on hESCs homeostasis.

Background and Objectives: Lung adenocarcinoma is a leading cause of cancer-related mortality despite recent therapeutic advances. Cancer stem cells have gained increasing attention due to their ability to induce cancer cell proliferation through self-renewal and differentiation into multiple cell lineages. OCT4 and LIN28 (and their homologs A and B) have been identified as key regulators of pluripotency in mammalian embryonic (ES) and induced stem (IS) cells, and they are the crucial regulators of cancer progression. However, their exact role in lung adenocarcinoma has not yet been clarified. Materials and Methods: The aim of this study was to explore the role of the pluripotency factors OCT4 and LIN28 in a cohort of surgically resected human lung adenocarcinomas to reveal possible biomarkers for lung adenocarcinoma prognosis and potential therapeutic targets. The expressions of OCT4, LIN28A and LIN28B were analyzed in formalin-fixed, paraffin-embedded tissue samples from 96 patients with lung adenocarcinoma by immunohistochemistry. The results were analyzed with clinicopathologic parameters and were related to the prognosis of patients. Results: Higher OCT4 expression was related to an improved 5-year overall survival (OS) rate (p < 0.001). Nuclear LIN28B expression was lower in stage I and II tumors (p < 0.05) compared to advanced stage tumors. LIN28B cytoplasmic expression was associated with 5-year OS rates not only in univariate (p < 0.005), but also in multivariate analysis (where age, gender, histopathological subtype and stage were used as cofactors, p < 0.01 HR = 2.592). Patients with lower LIN28B expression showed improved 5-year OS rates compared to patients with increased LIN28B expression. Conclusions: Our findings indicate that OCT4 and LIN28B are implicated in lung adenocarcinoma progression and prognosis outcome; thus, they serve as promising prognostic biomarkers and putative therapeutic targets in lung adenocarcinomas.