Search Results (1,286)

An overwhelming majority of cancers exhibit telomere length reduction and differentiation markers consistent with a post-stem cell of origin. On the other hand, telomere shortening/damage is believed to protect cells from malignant transformation through induction of apoptosis. However, increased cancer incidence in the absence of apoptotic factors like p53 may suggest a favorable role of telomere shortening/damage in cancer development. Some findings suggest that telomere shortening may induce architectural changes in telomeric chromatin, such as those underlying the telomere position effect that support telomere maintenance of some tumors Here, we propose that several signaling pathways, in conjunction with telomere shortening/damage, may result in the release of Rap1 from telomeres. Its subsequent interaction with the embryonic stem cell marker Zscan4 may support immortalization and malignant transformation of the target cell. Full article

Desmosomal junctions provide structural stability supporting concerted cardiomyocyte contractility. Previously, we demonstrated that a deficiency in the desmosomal transmembrane cadherin desmoglein 2 (Dsg2) reduces desmosome formation and disrupts cardiac morphogenesis, leading to excessive endothelial-to-hematopoietic cell transformation and embryonic lethality. It remained unclear whether this phenotype was specifically driven by Dsg2-deficiency or was a broader consequence of impaired desmosome adhesion. To address this question, we generated Pkp2^mt/mt mouse embryos lacking the desmosomal plaque protein Pkp2, which resulted in loss of desmosome formation. Despite the absence of cardiac wall rupture, Pkp2^mt/mt and some Pkp2^wt/mt presented accumulations of Ter-119⁺ blood cells and RUNX1⁺/CD44⁺ hematopoietic stem cells in the pericardial space. Remarkably, in Pkp2^mt/mt hearts, the epicardium was detached from the myocardium, contained rounded cells expressing the hematopoietic stem cell marker RUNX1, and showed altered intermediate filament expression. These findings suggest a potential trans-differentiation of the epicardial cells into hematopoietic cells. In conclusion, deficiencies in both Dsg2 and Pkp2 promote hematopoiesis in the developing murine heart but target different cell types, i.e., endothelial cells, which lack desmosomes, or desmosome-containing epicardial cells. Our results provide evidence for the involvement of Pkp2 in epicardial morphogenesis and remodeling. Full article

Granulosa cells (GCs) and ovarian putative stem cells (oPSCs) represent distinct but complementary populations within the mammalian ovary. While GCs have long been considered terminally differentiated and hormonally specialized, emerging evidence indicates that they retain epigenetic plasticity and, under defined conditions, can be reprogrammed into cells exhibiting pluripotent-like features. In contrast, oPSCs, including oogonial stem cells (OSCs) and very small embryonic-like stem cells (VSELs), are naturally multipotent and capable of spontaneous or inducible differentiation into neural, endothelial, and other somatic lineages. Both cell types express stemness-related markers, such as OCT4, SOX2, and c-KIT, and demonstrate potential for self-renewal and lineage conversion. Recent advances in chemical modulation of epigenetic reprogramming, particularly with agents from the family of non-specific DNA methyltransferase (DNMT) inhibitors, such as 5-azacytidine (5-azaC), highlight the feasibility of generating functional, lineage-specific derivatives of GCs or oPSCs without genetic manipulation. Not without significance is also the fact that extended/high-dose 5-azaC-mediated modulation can induce cell senescence or apoptotic/necrotic death. Therefore, dosing must be carefully titrated, which strongly supports a dose- and/or time-dependent mechanism for 5-azaC-based epigenetic modification in treated cells. This study aims to summarize the molecular and functional properties of mammalian GCs and oPSCs, emphasizing their applicability in regenerative medicine and reproductive bioengineering, with a focus on safe, patient-specific cell-based therapies. Full article

Serum-free suspension culture technology for animal cells involves the division and proliferation of cells in serum-free medium as single cells or cell clusters within shaking flasks or bioreactors. This approach enables large-scale cell culture, enhances the yield and quality of biopharmaceuticals, reduces costs, and broadens the applications of animal cells. Serum-free suspension culture of adherent cells (e.g., Madin–Darby canine kidney (MDCK), Chinese hamster ovary (CHO), Vero, baby hamster kidney (BHK-21), and human embryonic kidney (HEK293) cells) has been successfully achieved through direct or indirect adaptation, medium optimization, and genetic engineering. Additionally, novel suspension cell lines, such as duck embryonic stem (EB66) and human retinoblastoma (PER.C6) cells, have been developed as potential new substrates for biopharmaceutical production. This review examines animal cell suspension culture technology and its applications in viral vaccines, recombinant proteins, and monoclonal antibodies, providing insights into the development and utilization of this important technology. Full article

Human induced pluripotent cells (hiPSCs), generated in vitro, represent a groundbreaking tool for tissue regeneration and repair. Understanding the metabolic intricacies governing hiPSCs is crucial for optimizing their performance across diverse environmental conditions and improving production strategies. To this end, in this work, we introduce hiPSCGEM01, the first genome-scale, context-specific metabolic model (GEM) uniquely tailored to fibroblast-derived hiPSCs, marking a clear distinction from existing models of embryonic and cancer stem cells. hiPSCGEM01 was developed using relevant genome expression data carefully selected from the Gene Expression Omnibus (GEO), and integrated with the RECON 3D framework, a comprehensive genome-scale metabolic model of human metabolism. Redundant and unused reactions and genes were identified and removed from the model. Key reactions, including those facilitating the exchange and transport of metabolites between extracellular and intracellular environments, along with all metabolites required to simulate the growth medium, were integrated into hiPSCGEM01. Finally, blocked reactions and dead-end metabolites were identified and adequately solved. Knockout simulations combined with flux balance analysis (FBA) were employed to identify essential genes and metabolites within the metabolic network, providing a comprehensive systems-level view of fibroblast-derived hiPSC metabolism. Notably, the model uncovered the unexpected involvement of nitrate and xenobiotic metabolism—pathways not previously associated with hiPSCs—highlighting potential novel mechanisms of cellular adaptation that merit further investigation. hiPSCGEM01 establishes a robust platform for in silico analysis and the rational optimization of in vitro experiments. Future applications include the evaluation and refinement of culture media, the design of new formulations, and the prediction of hiPSC responses under varying growth conditions, ultimately advancing both experimental and clinical outcomes. Full article

Human early embryogenesis remains unexplored due to limited access to human embryos for research purposes. Meanwhile, the number of natural early pregnancy terminations remains significant, and solving the problem requires a deep understanding of the developmental mechanisms of this period. Although assisted reproductive technologies (ART) utilize up-to-date approaches in culturing human embryos in vitro, characterization of the embryos is still based on visual evaluation and subjective assessment. In addition, embryonic development in animal models, such as rodents and cattle, correlates poorly with human embryonic development. Synthetic embryology presents a promising new approach for studying human embryos involving the creation of embryos without the use of haploid germ cells. Instead, diploid pluripotent stem cells (PSCs) in a given state of pluripotency, which is maintained under conditions of induction and/or inhibition of certain signaling pathways, are used. Synthetic embryo systems (SES) may become a successful alternative model for studying fundamental processes of human early preimplantation embryogenesis, exploring new methods of objective embryo qualification, and personalized approaches in ART. However, the question of whether SES models can be considered as full-fledged mimics of the embryo remains open. This review examines human blastocyst-like structures known as blastoids. It discusses their use as models, as well as the parameters that need to be modified to more accurately simulate the human blastocyst. Full article

Muscle growth is a critical determinant of meat yield and quality in livestock. Although follistatin (FST) is recognized as a key regulator of skeletal muscle development and fat metabolism, its specific function in geese remains largely unexplored. In this study, we identified two transcript variants of goose FST (gFST) in Zhedong White geese: gFST-X1 (1125 bp), encoding a 343-amino acid protein with a 28-amino acid signal peptide and four conserved domains, and gFST-X2, which contains a 243 bp insertion within the gFST-X1 transcript. RT-qPCR analysis revealed that gFST mRNA expression varied across tissues from female embryos (25 days), adults (70 days), and laying geese (270 days), as well as in skeletal muscle satellite cells (SMSCs) at embryonic day 16 (E16d). Overexpression of gFST in SMSCs resulted in 3596 differentially expressed genes (DEGs), including 2247 upregulated and 1349 downregulated genes (padj < 0.01). Key stemness markers (PAX7, PAX3) and myogenic regulators (MYOG, MYOD, MYF5) were significantly downregulated, whereas genes associated with lipid metabolism (PPARG, FABP5, ACSL5) and myosin-related processes (MYO1D, MYO1F, MYO1E) were markedly upregulated (padj < 0.01). Functional enrichment analysis linked these DEGs to the TGF-β, PPAR signaling, fatty acid metabolism, and Notch signaling pathways. These transcriptomic findings were further validated by qRT-PCR. Collectively, our results demonstrate the dual regulatory role of gFST in skeletal muscle development and provide new mechanistic insights into muscle development in geese. Full article

RNA modifications comprise a core epigenetic dimension of gene regulation; among these, N6-methyladenosine (m6A) and 5-methylcytosine (m5C) have been most intensively investigated. While the functions of m6A in stem cell biology have been well characterized, the contributions of m5C remain comparatively less well defined. This review focuses on m5C modifications catalyzed by the NSUN family of RNA methyltransferases and their roles in regulating stem cell identity, pluripotency, and differentiation. Evidence from embryonic and mesenchymal stem cells, as well as animal models, demonstrates that NSUN-mediated m5C is deposited on diverse RNA substrates, including rRNA, tRNA, mRNA, mitochondrial RNA, and enhancer RNAs, thereby influencing processes such as self-renewal, cell cycle progression, RNA stability, metabolic activation, and lineage specification. Disruption of m5C regulation often leads to developmental defects, underscoring its essential role during embryogenesis. Collectively, these findings establish m5C as a versatile and dynamic regulator in stem cell biology and underscore the need for future studies to delineate the roles of the NSUN family in stem cells and define the RNA targets of m5C. In addition, its broader implications for development, regenerative medicine, and disease, including cancer, as well as its potential interplay with other RNA modifications such as m6A and pseudouridine, remain important areas for further investigation. Full article

Cell-based therapeutics are redefining interventions for vision loss by enabling tissue replacement, regeneration, and neuroprotection. This review surveys contemporary cellular strategies in ophthalmology through the lenses of therapeutic effectiveness, translational readiness, and governance. We profile principal sources—embryonic and induced pluripotent stem cells, mesenchymal stromal cells, retinal pigment epithelium, retinal progenitor and limbal stem cells—and enabling platforms including extracellular vesicles, encapsulated cell technology and biomaterial scaffolds. We synthesize clinical evidence across age-related macular degeneration, inherited retinal dystrophies, and corneal injury/limbal stem-cell deficiency, and highlight emerging applications for glaucoma and diabetic retinopathy. Delivery routes (subretinal, intravitreal, anterior segment) and graft formats (single cells, sheets/patches, organoids) are compared using standardized structural and functional endpoints. Persistent barriers include GMP-compliant derivation and release testing; differentiation fidelity, maturation, and potency; genomic stability and tumorigenicity risk; graft survival, synaptic integration, and immune rejection despite ocular immune privilege; the scarcity of validated biomarkers and harmonized outcome measures and ethical, regulatory, and health-economic constraints. Promising trajectories span off-the-shelf allogeneic products, patient-specific iPSC-derived grafts, organoid and 3D-bioprinted tissues, gene-plus-cell combinations, and cell-free extracellular-vesicle therapeutics. Overall, cell-based therapies remain investigational. With adequately powered trials, methodological harmonization, long-term surveillance, scalable xeno-free manufacturing, and equitable access frameworks, they may eventually become standards of care; at present, approvals are limited to specific products/indications and regions, and no cell therapy is the standard of care for retinal disease. Full article

This study reports the construction and validation of a CAFLUX (Chemically Activated Fluorescent Expression) HepG2 reporter cell line engineered to express a histone H2B–green fluorescent protein (H2B–GFP) fusion protein under the control of a dioxin-responsive cytochrome P450 1A1 (CYP1A1) promoter. A lentiviral construct containing a synthetic promoter with multiple dioxin-responsive elements (DREs) upstream of the H2B–EGFP coding sequence was cloned into the pFUGW vector, packaged in human embryonic kidney (HEK) 293FT cells, and used to transduce HepG2 hepatocellular carcinoma cells. Stable clones obtained by limiting dilution were screened for GFP expression in response to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The resulting CAFLUX HepG2 cells exhibited dose-dependent nuclear GFP fluorescence when exposed to aryl hydrocarbon receptor (AhR) agonists, with limits of detection of approximately 0.01 pM for TCDD and 0.1 pM for benzo[a]pyrene (B[a]P), a polycyclic aromatic hydrocarbon (PAH). This reporter activity correlated with endogenous CYP1A1 mRNA expression as determined by quantitative polymerase chain reaction (qPCR), confirming that GFP signals reflected native transcriptional responses. In functional assays, curcumin suppressed GFP expression in a concentration-dependent manner and induced apoptotic morphology at higher doses, while extracellular vesicles (EVs) derived from adipose-derived stem cells (ADSCs) significantly reduced both GFP fluorescence and CYP1A1 mRNA levels, suggesting an inhibitory effect on AhR-driven transcription. The CAFLUX HepG2 reporter system therefore provides a sensitive and reproducible platform for real-time, nuclear-localized monitoring of AhR-mediated gene expression. Its responsiveness to both agonists and antagonists underscores its potential utility in toxicological evaluation, drug discovery, and the investigation of EV-mediated signaling in liver cancer models. Full article

Hematopoietic stem cell (HSC) therapy remains essential in treating blood disorders, autoimmune diseases, neurodegenerative conditions, and cancers. Despite its potential, challenges arise from the inherent heterogeneity of HSCs and the complexity of their regulatory niche. Recent advancements in single-cell RNA sequencing and chromatin accessibility sequencing have provided deeper insights into HSC markers and chromatin dynamics, highlighting the intricate balance between intrinsic and extrinsic regulatory mechanisms. Zebrafish models have emerged as valuable tools in HSC research, particularly through live imaging and cellular barcoding techniques. These models have allowed us to describe critical interactions between HSCs and embryonic macrophages, involving reactive oxygen species and calreticulin signaling. These are essential for ensuring HSC quality and proper differentiation, with implications for improving HSC transplant outcomes. Furthermore, the review examines clonal hematopoiesis, with a focus on mutations in epigenetic regulators such as DNMT3A, TET2, and ASXL1, which elevate the risk of myelodysplastic syndromes and acute myeloid leukemia. Emerging technologies, including in vivo cellular barcoding and CRISPR-Cas9 gene editing, are being investigated to enhance clonal diversity and target specific mutations, offering potential strategies to mitigate these risks. Additionally, macrophages play a pivotal role in maintaining HSC clonality and ensuring niche localization. Interactions mediated by factors such as VCAM-1 and CXCL12/CXCR4 signaling are crucial for HSC homing and the stress response, opening new therapeutic avenues for enhancing HSC transplantation success and addressing clonal hematopoiesis. This review synthesizes findings from zebrafish models, cutting-edge sequencing technologies, and novel therapeutic strategies, offering a comprehensive framework for advancing HSC biology and improving clinical outcomes in stem cell therapy and the treatment of hematologic diseases. Full article

Regenerative medicine holds significant promise for addressing diseases and irreversible damage that are challenging to treat with conventional methods, making it a prominent research focus in modern medicine. Research on stem cells, a key area within regenerative medicine due to their self-renewal capabilities, is expanding, positioning them as a novel therapeutic option. Stem cells, utilized in various treatments, are categorized based on their differentiation potential and the source tissue. The term ‘stem cell’ encompasses a broad spectrum of cells, which can be derived from embryonic tissues, adult tissues, or generated by reprogramming differentiated cells. These cells, applied across numerous medical disciplines including cardiovascular, neurological, and hematological disorders, as well as wound healing, demonstrate varying therapeutic applications based on their differentiation capacities, each presenting unique advantages and limitations. Nevertheless, the existing literature lacks a comprehensive synthesis examining stem cell therapy and its cellular subtypes across different medical specialties. This review addresses this lacuna by collectively categorizing contemporary stem cell research according to medical specialty and stem cell classification, offering an exhaustive analysis of their respective benefits and constraints, thereby elucidating multifaceted perspectives on the clinical implementation of this therapeutic modality. Full article

The morphogenesis of the primordial gut relies on signaling pathways such as Wnt, FGF, Notch, Hedgehog, and Hippo. Reciprocal crosstalk between the endoderm and mesoderm is integrated into the signaling pathways, resulting in craniocaudal patterning. These pathways are also involved in adult intestinal homeostasis including cell proliferation and specification of cell fate. Perturbations in this process can cause growth disturbances manifesting as adenomas, serrated lesions, and cancer. Significant differences have been observed between right and left colon cancers in the hindgut, and between the jejunoileum, appendix, and right colon in the midgut. The question is to what extent the embryology of the mid- and hindgut contributes to differences in the underlying tumor biology. This review examines the precursor lesions and consensus molecular subtypes (CMS) of colorectal cancer (CRC) to highlight the significance of embryology and tumor microenvironment (TME) in CRC. The three main precursor lesions, i.e., adenomas, serrated lesions, and inflammatory bowel disease-associated dysplasia, are linked to the CMS classification, which is based on transcriptomic profiling and clinical features. Both embryologic and micro-environmental underpinnings of the mid- and hindgut contribute to the differences in the tumors arising from them, and they may do so by recapitulating embryonic signaling cascades. This manifests in the range of CRC CMS and histologic cancer subtypes and in tumors that show multidirectional differentiation, the so-called stem cell carcinomas. Emerging evidence shows the limitations of CMS particularly in patients on systemic therapy who develop drug resistance. The focus is thus transitioning from CMS to specific components of the TME. Full article

The medical application of human embryonic stem cell technology has sparked ethical controversies, with the core issue being whether human embryos possess the same right to life as humans. According to classical Confucianism, humans are born from the essential Qi 精氣 (jingqi) of heaven and earth, making them the noblest beings in the world. Human embryos are the simple form of human life in its early stages, and as living human beings, they should therefore possess the legitimacy and justification to life. Confucianism advocates benevolence toward people 仁民 (renmin) and love for things 愛物 (aiwu) distinguishing between benevolence and love: benevolence toward people is benevolence, while love for all things is love. How people treat one another is how they should treat human embryos. Things exist to serve humanity; humans may utilise things but must not be treated as tools. Embryo life must not be harmed or sacrificed for the sake of saving human life. One should show benevolence to people and love to things. Therefore, the attitude toward human embryos should be “benevolence.” Human embryos inherently possess the potential to become human beings and do not require medical intervention to demonstrate their value. However, when humans extract and utilise stem cells from human embryos for their own benefit, this is tantamount to treating the embryos as things and reducing them to the status of things, thereby blurring the ethical boundaries between humans and things and disrupting the distinction between the recipients of benevolence and love. The extraction of human embryonic stem cells is ultimately an artificial technological achievement. Humans are not superior beings to heaven, and such practices must be confined within the moral framework of technological ethics and bioethics. Notwithstanding the technological advancements that have furnished humans with contemporary instruments, the necessity for a sense of awe for the heaven remains. Full article

Background: Infertility remains a significant global health challenge, affecting approximately 15% of couples worldwide. In vitro fertilization (IVF) has transformed reproductive medicine; however, challenges such as low success rates in older patients, ovarian insufficiency, endometrial dysfunction, and male infertility continue to limit outcomes. Objective: This review aims to summarize the principles of IVF and explore the potential role of stem cells in enhancing IVF outcomes, with particular attention to applications in both women and men, as well as the accompanying ethical considerations. Summary: Stem cell research has introduced novel therapeutic opportunities, including ovarian rejuvenation, endometrial regeneration, sperm quality enhancement, and the development of synthetic embryo models. Mesenchymal stem cells (MSCs), embryonic stem cells (ESCs), and induced pluripotent stem cells (iPSCs) demonstrate regenerative properties that may help to overcome current reproductive limitations. Despite encouraging findings from preclinical and early clinical studies, challenges such as tumorigenesis, genetic instability, and ethical controversies remain major barriers to translation. Conclusions: IVF continues to serve as a cornerstone of assisted reproductive technology (ART). Stem cell-based approaches represent an exciting frontier that could expand the therapeutic possibilities of IVF. Careful clinical validation, international regulatory harmonization, and robust ethical oversight will be essential to ensuring safe and equitable implementation. Full article