Revisiting Pluripotency Acquisition: A Unified Framework for Reprogramming Strategies

mRNA translational dynamics mediates totipotent-like reprogramming.

Embryonic stem cells (ESCs) are characterized by their dual capacity for self-renewal and differentiation into all cell types of the embryonic lineage. A subpopulation known as 2-cell-like cells (2CLCs), which recapitulate key molecular and metabolic features of totipotent 2-cell blastomeres, has been identified within cultured mouse ESC populations. While transcriptional regulation, epigenetic modifications, and chromatin reorganization are known to be critical for the reprogramming of pluripotent ESCs into a totipotent-like state, the role of translational control in this process remains poorly understood. Using an inducible 2CLC model, we performed transcriptome-wide profiling of mRNA translation and found that global translation efficiency dynamically decreases during the early phase of totipotent-like reprogramming, correlating with reduced TORC1 signaling and translation initiation. In the later phase, although overall mitochondrial mass declines, mitochondrial translation is selectively upregulated and exhibits high translational efficiency. Importantly, pharmacological inhibition of mitochondrial translation suppressed the expression of canonical 2-cell transcripts and impaired the transition from ESCs to 2CLCs. Together, these results demonstrate that coordinated regulation of both cytosolic and mitochondrial translation during totipotent-like reprogramming, offering a new perspective for understanding cell fate determination.

IRAK4 constrains cellular plasticity during chemically-induced cell fate reprogramming into multiple lineages

Chemical reprogramming holds transformative potential for regenerative medicine. However, the regulatory mechanisms governing cell fate transitions are not well understood. Here, we identify Interleukin-1 Receptor-Associated Kinase 4 (IRAK4) as a barrier to multi-lineage reprogramming. Pharmacological inhibition of IRAK4 enhances the reprogramming of mouse embryonic fibroblasts (MEFs) through a chemically activated multi-lineage priming (CaMP) state and extraembryonic endoderm (XEN)-like intermediates, increasing colony formation, and the expression of core XEN regulators (Sox17, Gata4, Sall4, and Foxa2). Genetic knockdown of Irak4 similarly accelerates reprogramming, whereas its overexpression blocks cell fate transitions. IRAK4 inhibition enhances chromatin accessibility and reshapes cell cycle dynamics, characterized by G0/G1 shortening and G2/M lengthening, potentially contributing to multi-lineage state establishment. Furthermore, IRAK4 suppression enhances the direct conversion of MEFs to neuron-like and hepatocyte-like cells, which exhibit enhanced functional maturity, including increased glycogen storage and improved detoxification capacity. Our findings establish IRAK4 as a regulator that constrains cellular plasticity potentially by coordinating chromatin accessibility and cell cycle dynamics. IRAK4 is a barrier to chemical reprogramming and lineage conversion. Pharmacological or genetic inhibition of IRAK4 enhances multi-lineage priming, accelerates reprogramming, and improves the functional maturity of directly converted neuron-like and hepatocyte-like cells. IRAK4 inhibition promotes the chemical reprogramming of mouse embryonic fibroblasts through a CaMP state and XEN-like intermediates, increasing colony formation and the expression of core XEN regulators (Sox17, Gata4, Sall4, Foxa2). IRAK4 suppression enhances chromatin accessibility and reshapes cell cycle dynamics, which may facilitate the establishment of multi-lineage states. Inhibition of IRAK4 boosts direct conversion to neuron-like and hepatocyte-like cells. IRAK4 inhibition promotes the chemical reprogramming of mouse embryonic fibroblasts through a CaMP state and XEN-like intermediates, increasing colony formation and the expression of core XEN regulators (Sox17, Gata4, Sall4, Foxa2). IRAK4 suppression enhances chromatin accessibility and reshapes cell cycle dynamics, which may facilitate the establishment of multi-lineage states. Inhibition of IRAK4 boosts direct conversion to neuron-like and hepatocyte-like cells. IRAK4 is a barrier to chemical reprogramming and lineage conversion. Pharmacological or genetic inhibition of IRAK4 enhances multi-lineage priming, accelerates reprogramming, and improves the functional maturity of directly converted neuron-like and hepatocyte-like cells.

Harnessing Endogenous Plasticity Rather than Reprogramming of Mature Cells Will Advance Regenerative Medicine, Cancer Treatment and Rejuvenation.

Recognising the central role of VSELs/progenitors and their niche in maintaining tissue homeostasis in vivo could resolve existing roadblocks and guide more effective endogenous regenerative therapies for diseased tissues and age-related dysfunctions.

Induced pluripotent stem cell reprogramming: methodological evolution and challenges in clinical translation

This review summarizes the trajectory of iPSC reprogramming technologies and identifies the core “translational triltrilas”, namely, the inherent tradeoffs between security, homogeneity, and scalability, and proposes a comprehensive strategy to overcome these bottlenecks.

Induced pluripotent stem cells from discovery to translation.

Modeling myeloid cell development in health and disease using induced pluripotent stem cells

Key applications of iPSC technology in hemato-oncology are summarized, its major advantages and current limitations are discussed, and emerging directions are highlighted, including scalable iPSC-derived blood cell therapies for inherited and acquired bone marrow failure syndromes and leukemia.