The developmental potential within pluripotent cells in the canonical model is restricted to embryonic tissues, whereas totipotent cells can differentiate into both embryonic and extraembryonic tissues. Currently, the ability to culture in vitro totipotent cells possessing molecular and functional features like those of an early embryo in vivo has been a challenge. Recently, it was reported that treatment with a single spliceosome inhibitor, pladienolide B (plaB), can successfully reprogram mouse pluripotent stem cells into totipotent blastomere-like cells (TBLCs) in vitro. The TBLCs exhibited totipotency transcriptionally and acquired expanded developmental potential with the ability to yield various embryonic and extraembryonic tissues that may be employed as novel mouse developmental cell models. However, it is disputed whether TBLCs are ‘true’ totipotent stem cells equivalent to in vivo two-cell stage embryos. To address this question, single-cell RNA sequencing was applied to TBLCs and cells from early mouse embryonic developmental stages and the data were integrated using canonical correlation analyses. Differential expression analyses were performed between TBLCs and multi-embryonic cell stages to identify differentially expressed genes. Remarkably, a subpopulation within the TBLCs population expressed a high level of the totipotent-related genes Zscan4s and displayed transcriptomic features similar to mouse two-cell stage embryonic cells. This study underscores the subtle differences between in vitro derived TBLCs and in vivo mouse early developmental cell stages at the single-cell transcriptomic level. Our study has identified a new experimental model for stem cell biology, namely ‘cluster 3’, as a subpopulation of TBLCs that can be molecularly defined as near totipotent cells.

Colorectal cancer (CRC) is a leading cause of cancer‑associated mortality worldwide; therefore, there is an emerging need for novel experimental models that allow for the identification and validation of biomarkers for CRC‑specific progression. In the present study, a repeated sphere‑forming assay was used as a strategy to select a malignant subpopulation from a CRC cell line, namely HCT116. The assay was validated by confirming that canonical stemness markers were upregulated in the sphere state at every generation of the selection assay. The resulting subpopulation, after eight rounds of selection, exhibited increased sphere‑forming capacity in vitro and increased tumorigenicity in vivo. Furthermore, dipeptidase 1 (DPEP1) was identified as the major differentially expressed gene in the selected clone, and its depletion suppressed the elevated sphere‑forming capacity in vitro and tumorigenicity in vivo. Overall, the present study established an experimental strategy to isolate a malignant subpopulation from a CRC cell line. Additionally, results from the present model revealed that DPEP1 may serve as a promising prognostic biomarker for CRC.

Oligodendrocytes are glial cells located in the central nervous system (CNS) that play essential roles in the transmission of nerve signals and in the neuroprotection of myelinated neurons. The dysfunction or loss of oligodendrocytes leads to demyelinating diseases such as multiple sclerosis (MS). To treat demyelinating diseases, the development of a therapy that promotes remyelination is required. In the present study, we established an in vitro method to convert human fibroblasts into induced oligodendrocyte-like cells (iOLCs) in 3 days. The induced cells displayed morphologies and molecular signatures similar to oligodendrocytes after treatment with valproic acid and exposure to the small molecules Y27632, SU9516, and forskolin (FSK). To pursue the development of a cell-free remyelination therapy in vivo, we used a cuprizone-induced demyelinated mouse model. The small molecules (Y27632, SU9516, and FSK) were directly injected into the demyelinated corpus callosum of the mouse brain. This combination of small molecules rescued the demyelination phenotype within two weeks as observed by light and electron microscopy. These results provide a foundation for exploring the development of a treatment for demyelinating diseases via regenerative medicine.

Direct chemical reprogramming provides a potentially scalable approach for generating retinal lineage-associated cells without genetic manipulation. In this study, human Tenon’s capsule fibroblasts were converted into retinal progenitor-like cells using a defined small-molecule cocktail. Retinal lineage-associated features were evaluated by immunofluorescence staining, quantitative reverse-transcription PCR, Western blot analysis, and bulk RNA sequencing, showing upregulation of neural and retinal markers, including VSX2, and transcriptomic remodeling consistent with transcriptional features associated with neuronal differentiation programs. Functional responsiveness was assessed by glutamate-evoked intracellular calcium imaging, revealing glutamate-responsive intracellular calcium dynamics in induced cells but not in parental fibroblasts. For in vivo assessment, induced cells were delivered via intravitreal transplantation in Wistar rats and subretinal transplantation in Long–Evans rats. One month after transplantation, structural and functional evaluations using optical coherence tomography, electroretinography, and histological analyses showed localized alterations in retinal structure at the subretinal injection site, while no significant differences were observed in scotopic ERG responses under the present experimental conditions. In contrast, fibroblast transplantation showed more prominent structural alterations under similar conditions. Human nuclei-positive signals were detectable in a subset of eyes, exhibiting focal and heterogeneous distribution within retinal regions at the one-month endpoint. Collectively, these suggest the induction of retinal lineage-associated molecular and functional features, with short-term functional tolerability observed in vivo under the present experimental conditions.