20 nM Pladienolide B +6 h treatment = totipotent stem cells? The new method captures totipotency

In a groundbreaking study published in Science China Life Sciences, a research team led by Dr. Yang Yang and Dr. Xi Wang from Nanjing Medical University has made a significant breakthrough in stem cell biology. They demonstrated that a short-term, high-dose treatment of Pladienolide B (PlaB) can reprogram classical mouse embryonic stem cells (mESCs) into transient totipotent blastomere-like stem cells (tTBLCs). These tTBLCs exhibit remarkable developmental potential, capable of differentiating into both embryonic and extra-embryonic cell lineages. Moreover, they possess the unique ability to self-organize into blastocyst-like structures, known as blastoids, which closely mimic the early stages of embryonic development. This discovery provides new insights into cellular reprogramming and the mechanisms underlying totipotency, offering promising avenues for regenerative medicine and developmental research.

Totipotent State Induction

The study revealed that a brief 6-hour exposure to 20 nM PlaB effectively activated totipotency-associated genes in mESCs while maintaining pluripotent gene expression. This transient pharmacological intervention successfully reprogrammed mESCs into a metastable totipotent-like state, termed tTBLCs, characterized by expanded lineage potential.

Blastoid Formation

Remarkably, tTBLCs exhibited autonomous self-organization capabilities, forming three-dimensional blastoids that closely recapitulated the spatial organization of natural pre-implantation embryos. These blastoids contained all three cardinal lineages: trophectoderm (TE), epiblast (EPI), and primitive endoderm (PrE), mirroring the cellular diversity of native blastocysts.

Developmental Potential

The tTBLC-derived blastoids demonstrated extended developmental competence, progressing to form post-implantation egg-cylinder-like structures both in vitro and in vivo. Although developmental efficiency remained suboptimal compared to natural embryos, this breakthrough highlights tTBLCs' unique capacity to model peri-implantation developmental events.

Transcriptional Similarity

Transcriptome analysis revealed transcriptional parallels between tTBLC-blastoids and mouse E3.5-E4.5 blastocysts, with pronounced enrichment of trophoblast lineage markers. This lineage bias positions tTBLCs as a powerful in vitro platform for investigating early trophoblast specification and placental development mechanisms.

In summary, this work establishes a rapid, chemically defined strategy for generating blastoid-competent stem cells through transient pharmacological modulation. Beyond advancing fundamental understanding of totipotency and embryogenesis, the tTBLC platform holds transformative potential for applications ranging from high-throughput developmental toxicity screening to regenerative medicine strategies, bridging the gap between stem cell biology and translational research.