Regulation of Oct4 in stem cells and neural crest cells

Induction of feline fetal fibroblasts into pluripotent stem cells using cat-derived reprogramming factors

There are few studies on the establishment of induced pluripotent stem cells (iPSCs) in cats. Although induction using heterologous reprogramming factors delivered via viral vectors has been reported, its safety and reprogramming efficiency still require improvement. In addition, the reprogramming mechanism needs further elucidation. In this study, we constructed a series of expression vectors for cat-derived reprogramming transcription factors based on the piggyBac transposon system and transfected various factor combinations into cat fetal fibroblasts (CFFs) under different electroporation conditions to generate cat iPSCs (ciPSCs). Additionally, the specific roles of these factors in reprogramming were investigated. The results showed that under the optimized electroporation conditions (DMEM/F12 buffer, 300 V, 10 ms pulse duration, 2 pulses, 25 μg plasmid DNA, and 4 mm cuvette), the survival rate and transfection efficiency of CFFs reached 64 % and 67.8 %, respectively. Based on this condition, a seven-factor combination (cOSKM + pNL + SV40 Large T) was confirmed as a better inducer for establishing ciPSCs. The obtained ciPSCs exhibit good pluripotency and passaging stability. They express stemness-related genes and proteins, and can form embryoid bodies (EBs) capable of differentiating into all three germ layers. OCT4 (O), SOX2 (S), KLF4 (K), and c-MYC (M) play important cooperative and synergistic roles in the mesenchymal-to-epithelial transition (MET) during the initial stages of reprogramming, while the supplement of NANOG (N) and LIN28 (L) can further promote MET and is important for successful reprogramming. It lays a foundation for the further breeding of cloned and genetically modified cats, and provides a tool for studying embryonic developmental diseases, screening drugs, and applying to tissue regeneration.

Three-Dimensional Trilineage Differentiation Conditions for Human Induced Pluripotent Stem Cells

Human induced pluripotent stem cells (hiPSCs) hold great potential for regenerative medicine. However, optimizing their differentiation into specific lineages within three-dimensional (3D) scaffold-based culture systems that mimic in vivo environments remains challenging. This study examined the trilineage differentiation of hiPSCs under various 3D conditions using synthetic peptide hydrogel matrices with and without embryoid body (EB) medium induction. hiPSC 3D colonies (spheroids), naturally formed from single cells or small clusters in 3D culture, were used for differentiation into the three germ lineages. Differentiated spheroids exhibited distinct morphological characteristics and significantly increased expression of key lineage-specific markers-FOXA2 (endoderm), Brachyury (mesoderm), and PAX6 (ectoderm)-compared to undifferentiated controls. Marker expression varied depending on the 3D culture conditions. Differentiation efficiency improved significantly, increasing from 16% to 71% for endoderm, 61% to 80% for mesoderm, and 35% to 48% for ectoderm, by selecting the appropriate 3D matrix and applying EB induction. Comprehensive data analysis from RT-qPCR, immunocytochemistry staining, and flow cytometry confirmed that the Synthegel Spheroid (SGS) is a viable 3D matrix for evaluating all three germ lineages using a commercial trilineage differentiation kit. While EB induction is essential for endodermal differentiation, it is not required for mesodermal and ectodermal lineages. These findings are valuable not only for screening initial differentiation potential at the lineage level but also for optimizing 3D differentiation protocols for deriving somatic cells from hiPSCs.

Genetic and Molecular Characterization of H9c2 Rat Myoblast Cell Line

This study presents a comprehensive genetic characterization of the H9c2 cell line, a widely used model for cardiac myoblast research. We established a short tandem repeat (STR) profile for H9c2 that is useful to confirm the identity and stability of the cell line. Additionally, we prepared H9c2 metaphase chromosomes and performed karyotyping and molecular cytogenetics to further investigate chromosomal characteristics. The genetic analysis showed that H9c2 cells exhibit chromosomal instability, which may impact experimental reproducibility and data interpretation. Next-generation sequencing (NGS) was performed to analyze the transcriptome, revealing gene expression patterns relevant to cardiac biology. Western blot analysis further validated the expression levels of selected cardiac genes identified through NGS. Additionally, Phalloidin staining was used to visualize cytoskeletal organization, highlighting the morphological features of these cardiac myoblasts. Our findings collectively support that H9c2 cells are a reliable model for studying cardiac myoblast biology, despite some genetic alterations identified resembling sarcoma cells. The list of genes identified through NGS analysis, coupled with our comprehensive genetic analysis, will serve as a valuable resource for future studies utilizing this cell line in cardiovascular medicine.

Integrative analysis of serum proteomics and transcriptomics in hepatitis C

OBJECT

Hepatitis C is a contagious disease caused by infection with the hepatitis C virus (HCV) through blood and mother-to-child routes. This study intends to characterize the serum molecular features of hepatitis C using proteomics and transcriptomics.

METHODS

Ctrl (normal population), HCV (population with previous HCV infection), and chronic HCV (patients with persistent HCV infection) groups were set up, and the expression profiles of the proteomes and transcriptomes of serum samples were identified using TMT and RNA-seq. Bioinformatics was applied to perform enrichment analysis and PPI network construction of differentially expressed proteins/genes (DEPs/DEGs). RT-qPCR and western blot verified the expression differences of DEPs/DEGs.

RESULTS

Compared to the Ctrl group, the HCV group had 356 DEPs in serum; compared to the HCV group, the chronic HCV group had 381 DEPs in serum. DEPs are predominantly immunoglobulins and exosomal proteins that regulate carbon dioxide transport, initiation of transcription, immune responses, and bacterial and viral infections. HSPA4, HSPD1, COPS5, PSMD2 and TCP1 are key HCV-associated proteins in DEPs. The HCV group had 684 DEGs compared to the Ctrl group, and the chronic HCV group had 350 DEGs compared to the HCV group. DEGs primarily encode the extracellular matrix and regulate wound healing, cellular communication, oxidative stress, cell adhesion, viral infection, and immunity. KIF11, CENPE, TTK, CDC20 and ASPM are HCV-related hub genes in DEGs. Combined analyses revealed interactions between DEPs and DEGs, especially EIF4A3, MNAT1, and UBE2D1. Moreover, the expression patterns of EIF4A3, EIF2B1, MNAT1, SNRNP70, and UBE2D1 in DEPs/DEGs from Ctrl, HCV, and chronic HCV groups were consistent with the sequencing results.

CONCLUSION

EIF4A3, EIF2B1, MNAT1, SNRNP70, and UBE2D1 are involved in the process of HCV infection and pathogenesis, and they may be potential biomarkers for the treatment of patients with hepatitis C.

Maintenance of pluripotency-like signature in the entire ectoderm leads to neural crest stem cell potential

The ability of the pluripotent epiblast to contribute progeny to all three germ layers is thought to be lost after gastrulation. The later-forming neural crest (NC) rises from ectoderm and it remains poorly understood how its exceptionally high stem-cell potential to generate mesodermal- and endodermal-like derivatives is obtained. Here, we monitor transcriptional changes from gastrulation to neurulation using single-cell-Multiplex-Spatial-Transcriptomics (scMST) complemented with RNA-sequencing. We show maintenance of pluripotency-like signature (Nanog, Oct4/PouV, Klf4-positive) in undecided pan-ectodermal stem-cells spanning the entire ectoderm late during neurulation with ectodermal patterning completed only at the end of neurulation when the pluripotency-like signature becomes restricted to NC, challenging our understanding of gastrulation. Furthermore, broad ectodermal pluripotency-like signature is found at multiple axial levels unrelated to the NC lineage the cells later commit to, suggesting a general role in stemness enhancement and proposing a mechanism by which the NC acquires its ability to form derivatives beyond "ectodermal-capacity" in chick and mouse embryos.

Human Oral Mucosa as a Potentially Effective Source of Neural Crest Stem Cells for Clinical Practice

We report in this study on the isolation and expansion of neural crest stem cells (NCSCs) from the epithelium of oral mucosa (OM) using reagents that are GMP-certified and FDA-approved for clinical use. Characterization analysis showed that the levels of keratins K2, K6C, K4, K13, K31, and K15-specific to OM epithelial cells-were significantly lower in the experimental NCSCs. While SOX10 was decreased with no statistically significant difference, the earliest neural crest specifier genes SNAI1/2, Ap2a, Ap2c, SOX9, SOX30, Pax3, and Twist1 showed a trend in increased expression in NCSCs. In addition, proteins of Oct4, Nestin and Noth1 were found to be greatly expressed, confirming NCSC multipotency. In conclusion, our study showed that the epithelium of OM contains NCSCs that can be isolated and expanded with clinical-grade reagents to supply the demand for multipotent cells required for clinical applications in regenerative medicine. Supported by Emmaus Medical Inc.

Recognition of H2AK119ub plays an important role in RSF1-regulated early Xenopus development

Polycomb group (PcG) proteins are key regulators of gene expression and developmental programs via covalent modification of histones, but the factors that interpret histone modification marks to regulate embryogenesis are less studied. We previously identified Remodeling and Spacing Factor 1 (RSF1) as a reader of histone H2A lysine 119 ubiquitination (H2AK119ub), the histone mark deposited by Polycomb Repressive Complex 1 (PRC1). In the current study, we used Xenopus laevis as a model to investigate how RSF1 affects early embryonic development and whether recognition of H2AK119ub is important for the function of RSF1. We showed that knockdown of Xenopus RSF1, rsf1, not only induced gastrulation defects as reported previously, but specific targeted knockdown in prospective neural precursors induced neural and neural crest defects, with reductions of marker genes. In addition, similar to knockdown of PRC1 components in Xenopus, the anterior-posterior neural patterning was affected in rsf1 knockdown embryos. Binding of H2AK119ub appeared to be crucial for rsf1 function, as a construct with deletion of the UAB domain, which is required for RSF1 to recognize the H2AK119ub nucleosomes, failed to rescue rsf1 morphant embryos and was less effective in interfering with early Xenopus development when ectopically expressed. Furthermore, ectopic deposition of H2AK119ub on the Smad2 target gene gsc using a ring1a-smad2 fusion protein led to ectopic recruitment of RSF1. The fusion protein was inefficient in inducing mesodermal markers in the animal region or a secondary axis when expressed in the ventral tissues. Taken together, our results reveal that rsf1 modulates similar developmental processes in early Xenopus embryos as components of PRC1 do, and that RSF1 acts at least partially through binding to the H2AK119ub mark via the UAB domain during development.

Early development of the human embryonic testis

Human gonadal development culminating in testicular differentiation is described through analysis of histologic sections derived from 33-day to 20-week human embryos/fetuses, focusing on early development (4-8 weeks of gestation). Our study updates the comprehensive studies of Felix (1912), van Wagenen and Simpson (1965), and Juric-Lekic et al. (2013), which were published in books and thus are unsearchable via PubMed. Human gonads develop from the germinal ridge, a thickening of coelomic epithelium on the medial side of the urogenital ridge. The bilateral urogenital ridges contain elements of the mesonephric kidney, namely the mesonephric duct, mesonephric tubules, and mesonephric glomeruli. The germinal ridge, into which primordial germ cells migrate, is initially recognized as a thickening of coelomic epithelium on the urogenital ridge late in the 4th week of gestation. Subsequently, in the 5th week of gestation, a dense mesenchyme develops sub-adjacent to the epithelium of the germinal ridge, and together these elements bulge into the coelomic cavity forming bilateral longitudinal ridges attached to the urogenital ridges. During development, primordial cells migrate into the germinal ridge and subsequently into testicular cords that form within the featureless dense mesenchyme of the germinal ridge at 6-8 weeks of gestation. The initial low density of testicular cords seen at 8 weeks remodels into a dense array of testicular cords surrounded by α-actin-positive myoid cells during the second trimester. Human testicular development shares many features with that of mice being derived from 4 elements: coelomic epithelium, sub-adjacent mesenchyme, primordial germ cells, and the mesonephros.