Published papers

Extended pluripotent stem cells (EPSCs) derived from mice and humans showed an enhanced potential for chimeric formation. By exploiting transcriptomic approaches, we assessed the differences in gene expression profile between extended EPSCs derived from mice and humans, and those newly derived from the common marmoset (marmoset; Callithrix jacchus). Although the marmoset EPSC-like cells displayed a unique colony morphology distinct from murine and human EPSCs, they displayed a pluripotent state akin to embryonic stem cells (ESCs), as confirmed by gene expression and immunocytochemical analyses of pluripotency markers and three-germ-layer differentiation assay. Importantly, the marmoset EPSC-like cells showed interspecies chimeric contribution to mouse embryos, such as E6.5 blastocysts in vitro and E6.5 epiblasts in vivo in mouse development. Also, we discovered that the perturbation of gene expression of the marmoset EPSC-like cells from the original ESCs resembled that of human EPSCs. Taken together, our multiple analyses evaluated the efficacy of the method for the derivation of marmoset EPSCs.

Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like episodes (MELAS) are mitochondrial disorders most commonly caused by a m.3243A>G variant in mitochondrial tRNALeu . To investigate the pathophysiology of MELAS, we generated brain organoids from multiple induced pluripotent stem cell (iPSC) lines derived from a patient with MELAS carrying the m.3243A>G variant. These lines share an identical nuclear genetic background but differ in their heteroplasmy levels involving the m.3243A>G variant. We observed significant differences in organoid size, morphology, and neural induction efficiency, which correlated with the degree of heteroplasmy. Dissociated neurons from the organoids were transferred into a 2D-culture system, which is convenient and suitable for high-throughput drug screening. The organoids also exhibited significant differences in the formation of neural networks, depending on heteroplasmy levels. Our results suggest that patient-derived iPSC-based organoid models represent a useful platform for studying MELAS mechanisms and for drug screening. This video presents comprehensive and user-friendly methods, including protocols for generating organoids and evaluating phenotypes.

Induced pluripotent stem cells (iPSCs) are capable of providing an unlimited source of cells from all three germ layers and germ cells. The derivation and usage of iPSCs from various animal models may facilitate stem cell-based therapy, gene-modified animal production, and evolutionary studies assessing interspecies differences. However, there is a lack of species-wide methods for deriving iPSCs, in particular by means of non-viral and non-transgene-integrating (NTI) approaches. Here, we demonstrate the iPSC derivation from somatic fibroblasts of multiple mammalian species from three different taxonomic orders, including the common marmoset (Callithrix jacchus) in Primates, the dog (Canis lupus familiaris) in Carnivora, and the pig (Sus scrofa) in Cetartiodactyla, by combinatorial usage of chemical compounds and NTI episomal vectors. Interestingly, the fibroblasts temporarily acquired a neural stem cell-like state during the reprogramming. Collectively, our method, robustly applicable to various species, holds a great potential for facilitating stem cell-based research using various animals in Mammalia.