Derivation of induced pluripotent stem cells in Japanese macaque (Macaca fuscata)

Non-human primates are our closest relatives and are of special interest for ecological, evolutionary and biomedical research. The Japanese macaque (Macaca fuscata) has contributed to the progress of primatology and neurosciences over 60 years. Despite this importance, the molecular and cellular basis of the Japanese macaque remains unexplored since useful cellular tools are lacking. Here we generated induced pluripotent stem cells (iPSCs) from skin fibroblasts of the Japanese macaque with Sendai virus or plasmid vectors. The Japanese macaque iPSCs (jm-iPSCs) were established under feeder-free culture conditions, but feeder cells turned out to be essential for their maintenance. The jm-iPSCs formed human iPSC-like flat colonies which were positive for pluripotent antigens including alkaline phosphatase, SSEA4, and TRA-1-81. They also expressed endogenous OCT3/4, SOX2, L-MYC, and KLF4 and other pluripotent marker genes. The potential to differentiate into all three germ layers and neural stem cells was confirmed by embryoid body and neurosphere formation, respectively. The jm-iPSCs will provide a robust in vitro tool for investigating the underlying mechanisms of development and physiology studies with the Japanese macaque

Modeling of early neural development in vitro by direct neurosphere formation culture of chimpanzee induced pluripotent stem cells

iPS細胞を使ってチンパンジーの初期神経発生を誘導 --ヒト脳進化の解明に向けたiPS細胞研究に道--. 京都大学プレスリリース. 2020-03-17.Evolutionary developmental biology of our closest living relative, the chimpanzee (Pan troglodytes), is essential for understanding the origin of human traits. However, it is difficult to access developmental events in the chimpanzee in vivo because of technical and ethical restrictions. Induced pluripotent stem cells (iPSCs) offer an alternative in vitro model system to investigate developmental events by overcoming the limitations of in vivo study. Here, we generated chimpanzee iPSCs from adult skin fibroblasts and reconstructed early neural development using in vitro differentiation culture conditions. Chimpanzee iPSCs were established using straightforward methods, namely, lipofection of plasmid vectors carrying human reprogramming factors, combined with maintenance in a comprehensive feeder-free culture. Ultimately, direct neurosphere formation culture induced rapid and efficient differentiation of neural stem cells from chimpanzee iPSCs. Time course analysis of neurosphere formation demonstrated ontogenetic changes in gene expression profiles and developmental potency along an early neural development path from epiblasts to radial glia. Our iPSC culture system is a potent tool for investigating the molecular and cellular foundation underlying chimpanzee early neural development and better understanding of human brain evolution

Regulation of the MDM2-P53 pathway and tumor growth by PICT1 via nucleolar RPL11

PICT1 (also known as GLTSCR2) is considered a tumor suppressor because it stabilizes phosphatase and tensin homolog (PTEN), but individuals with oligodendrogliomas lacking chromosome 19q13, where PICT1 is located, have better prognoses than other oligodendroglioma patients. To clarify the function of PICT1, we generated Pict1-deficient mice and embryonic stem (ES) cells. Pict1 is a nucleolar protein essential for embryogenesis and ES cell survival. Even without DNA damage, Pict1 loss led to p53-dependent arrest of cell cycle phase G(1) and apoptosis. Pict1-deficient cells accumulated p53, owing to impaired Mdm2 function. Pict1 binds Rpl11, and Rpl11 is released from nucleoli in the absence of Pict1. In Pict1-deficient cells, increased binding of Rpl11 to Mdm2 blocks Mdm2-mediated ubiquitination of p53. In human cancer, individuals whose tumors express less PICT1 have better prognoses. When PICT1 is depleted in tumor cells with intact P53 signaling, the cells grow more slowly and accumulate P53. Thus, PICT1 is a potent regulator of the MDM2-P53 pathway and promotes tumor progression by retaining RPL11 in the nucleolu