A novel efficient feeder-free culture system for the derivation of human induced pluripotent stem cells.

In order to apply human embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs) to regenerative medicine, the cells should be produced under restricted conditions conforming to GMP guidelines. Since the conventional culture system has some issues that need to be addressed to achieve this goal, we developed a novel culture system. We found that recombinant laminin-511 E8 fragments are useful matrices for maintaining hESCs and hiPSCs when used in combination with a completely xeno-free (Xf) medium, StemFit™.

Promotion of direct reprogramming by transformation-deficient Myc.

Induced pluripotent stem cells (iPSCs) are generated from mouse and human fibroblasts by the introduction of three transcription factors: Oct3/4, Sox2, and Klf4. The proto-oncogene product c-Myc markedly promotes iPSC generation, but also increases tumor formation in iPSC-derived chimeric mice. We report that the promotion of iPSC generation by Myc is independent of its transformation property.

The organization of histone H3 modifications as revealed by a panel of specific monoclonal antibodies.

Histone modifications play critical roles in the epigenetic regulation of gene expression and in the maintenance of genome integrity. Acetylation and methylation of histone H3 are particularly important in gene activation and silencing. We generated and characterized a panel of mouse monoclonal antibodies that specifically recognize different modifications on K4, K9, and K27 residues on histone H3.

Generation of induced pluripotent stem cells without Myc from mouse and human fibroblasts.

Direct reprogramming of somatic cells provides an opportunity to generate patient- or disease-specific pluripotent stem cells. Such induced pluripotent stem (iPS) cells were generated from mouse fibroblasts by retroviral transduction of four transcription factors: Oct3/4, Sox2, Klf4 and c-Myc. Mouse iPS cells are indistinguishable from embryonic stem (ES) cells in many respects and produce germline-competent chimeras.

A novel histone exchange factor, protein phosphatase 2Cgamma, mediates the exchange and dephosphorylation of H2A-H2B.

In eukaryotic nuclei, DNA is wrapped around a protein octamer composed of the core histones H2A, H2B, H3, and H4, forming nucleosomes as the fundamental units of chromatin. The modification and deposition of specific histone variants play key roles in chromatin function. In this study, we established an in vitro system based on permeabilized cells that allows the assembly and exchange of histones in situ.

Sedative and anticonvulsant activities of goodyerin, a flavonol glycoside from Goodyera schlechtendaliana.

Goodyerin is a flavonol glycoside isolated from the whole plants of Goodyera schlechtendaliana which has been used as a substitute for the crude drug, Anoectochilus formosanus. The pharmacological properties of goodyerin were assayed for effects on spontaneous locomotor activity, on pentobarbital-induced hypnosis, and on anticonvulsant activity against picrotoxin-induced seizures in rodents. Goodyerin exhibited a significant and dose-dependent sedative and anticonvulsant effect.