Efficient Adhesion Culture of Human Pluripotent Stem Cells Using Laminin Fragments in an Uncoated Manner

ヒト多能性幹細胞の拡大培養法の簡便かつ低コスト化に成功 : 培養基質のコーティングを必要としない培養法を開発. 京都大学プレスリリース. 2017-01-31.We describe highly effective adhesion culture of human pluripotent stem cells (hPSCs) using laminin fragments without precoating. Culture substrates have been generally thought to exert a cell adhesion effect when they are precoated onto culture vessels. However, simple addition of laminin fragments to a cell suspension during passaging accelerated the adhesion of single dissociated hPSCs onto culture vessels that were not precoated with any culture substrate. Interestingly, similar to conventional precoating, the uncoated addition of laminin fragments supported robust adhesion of single hPSCs and maximum adhesion at a much lower concentration compared with precoating. Similar to precoating laminin fragments, hPSCs seeded with uncoated laminin fragments grew well without cell detachment and maintained pluripotency after continuous subculture. We tested other culture substrates, including full-length laminin and vitronectin, to support hPSC adhesion in the uncoated manner, but only laminin fragments had the potential for application in the uncoated manner. This cost-effective and time-efficient method may contribute to expansion of culture of hPSCs and accelerate the development of regenerative medicine using hPSCs

New insights into the catalytic active-site structure of multicopper oxidases

Structural models determined by X-ray crystallography play a central role in understanding the catalytic mechanism of enzymes. However, X-ray radiation generates hydrated electrons that can cause significant damage to the active sites of metalloenzymes. In the present study, crystal structures of the multicopper oxidases (MCOs) CueO from Escherichia coli and laccase from a metagenome were determined. Diffraction data were obtained from a single crystal under low to high X-ray dose conditions. At low levels of X-ray exposure, unambiguous electron density for an O atom was observed inside the trinuclear copper centre (TNC) in both MCOs. The gradual reduction of copper by hydrated electrons monitored by measurement of the Cu K-edge X-ray absorption spectra led to the disappearance of the electron density for the O atom. In addition, the size of the copper triangle was enlarged by a two-step shift in the location of the type III coppers owing to reduction. Further, binding of O2 to the TNC after its full reduction was observed in the case of the laccase. Based on these novel structural findings, the diverse resting structures of the MCOs and their four-electron O2-reduction process are discussed. © 2014 International Union of Crystallography

High Glucose Increases Metallothionein Expression in Renal Proximal Tubular Epithelial Cells

Metallothionein (MT) is an intracellular metal-binding, cysteine-rich protein, and is a potent antioxidant that protects cells and tissues from oxidative stress. Although the major isoforms MT-1 and -2 (MT-1/-2) are highly inducible in many tissues, the distribution and role of MT-1/-2 in diabetic nephropathy are poorly understood. In this study, diabetes was induced in adult male rats by streptozotocin, and renal tissues were stained with antibodies for MT-1/-2. MT-1/-2 expression was also evaluated in mProx24 cells, a mouse renal proximal tubular epithelial cell line, stimulated with high glucose medium and pretreated with the antioxidant vitamin E. MT-1/-2 expression was gradually and dramatically increased, mainly in the proximal tubular epithelial cells and to a lesser extent in the podocytes in diabetic rats, but was hardly observed in control rats. MT-1/-2 expression was also increased by high glucose stimulation in mProx24 cells. Because the induction of MT was suppressed by pretreatment with vitamin E, the expression of MT-1/-2 is induced, at least in part, by high glucose-induced oxidative stress. These observations suggest that MT-1/-2 is induced in renal proximal tubular epithelial cells as an antioxidant to protect the kidney from oxidative stress, and may offer a novel therapeutic target against diabetic nephropathy

Laminin E8 fragments support efficient adhesion and expansion of dissociated human pluripotent stem cells

Miyazaki, T. et al.. Laminin E8 fragments support efficient adhesion and expansion of dissociated human pluripotent stem cells. Nat. Commun. 3:1236 doi: 10.1038/ncomms2231 (2012)

Intramedullary injury combined with osteoporosis therapeutics regulates targeted local osteogenesis.

福岡歯科大学2022年

Pressure dependence of superconductivity in low- and high-T-c phases of (NH3)(y)NaxFeSe

We prepared two superconducting phases, which are called “low-Tc phase” and “high-Tc phase” of (NH3)yNaxFeSe showing Tc’s of 35 and 44 K, respectively, at ambient pressure, and studied the superconducting behavior and structure of each phase under pressure. The Tc of the 35 K at ambient pressure rapidly decreases with increasing pressure up to 10 GPa, and it remains unchanged up to 22 GPa. Finally, superconductivity was not observed down to 1.4 K at 29 GPa, i.e., Tc < 1.4K. The Tc of the 44 K phase also shows a monotonic decrease up to 15 GPa and it weakly decreases up to 25 GPa. These behaviors suggest no pressure-driven high-Tc phase (called “SC-II”) between 0 and 25 GPa for the low-Tc and high-Tc phases of (NH3)yNaxFeSe, differing from the behavior of (NH3)yCsxFeSe,which has a pressure-driven high-Tc phase (SC-II) in addition to the superconducting phase (SC-I) observed at ambient and low pressures. The Tc-c phase diagram for both low-Tc and high-Tc phases shows that the Tc can be linearly scaled with c (or FeSe plane spacing), where c is a lattice constant. The reason why a pressure-driven high-Tc phase (SC-II) was found for neither low-Tc nor high-Tc phases of (NH3)yNaxFeSe is fully discussed, suggesting a critical c value as the key to forming the pressure-driven high-Tc phase (SC-II). Finally, the precise Tc-c phase diagram is depicted using the data obtained thus far from FeSe codoped with a metal and NH3 or amine, indicating two distinct Tc-c lines below c = 17.5A°

MEF/ELF4 transactivation by E2F1 is inhibited by p53

Myeloid elf-1-like factor (MEF) or Elf4 is an E-twenty-six (ETS)-related transcription factor with strong transcriptional activity that influences cellular senescence by affecting tumor suppressor p53. MEF downregulates p53 expression and inhibits p53-mediated cellular senescence by transcriptionally activating MDM2. However, whether p53 reciprocally opposes MEF remains unex-plored. Here, we show that MEF is modulated by p53 in human cells and mice tissues. MEF expression and promoter activity were suppressed by p53. While we found that MEF promoter does not contain p53 response elements, intriguingly, it contains E2F consensus sites. Subsequently, we determined that E2F1 specifically binds to MEF promoter and transactivates MEF. Nevertheless, E2F1 DNA binding and transactivation of MEF promoter was inhibited by p53 through the association between p53 and E2F1. Furthermore, we showed that activation of p53 in doxorubicin-induced senescent cells increased E2F1 and p53 interaction, diminished E2F1 recruitment to MEF promoter and reduced MEF expression. These observations suggest that p53 downregulates MEF by associating with and inhibiting the binding activity of E2F1, a novel transcriptional activator of MEF. Together with previous findings, our present results indicate that a negative regulatory mechanism exists between p53 and MEF

Management of Natural History collections: criteria and parameters of evaluation

[ES] Las colecciones de historia natural son una herramienta básica para la investigación científica y el estudio de la distribución en el pasado de muchas especies, así como de la propia historia de la ciencia. Además del uso científico de estas colecciones, destacan otros como el histórico, el divulgativo-pedagógico y el estético. De ahí la importancia que tiene una gestión eficaz de las mismas, la cual implica diversos aspectos, que van desde la conservación y su mantenimiento, su inventario, ordenación y procesamiento informático hasta las múltiples tareas relacionadas con su uso en consultas, visitas, préstamos científicos y participación en actividades de carácter divulgativo. En este artículo se examinan los criterios para evaluar la gestión de las colecciones de historia natural y se definen una serie de parámetros, útiles para medir el estado de una colección y su evolución en el tiempo, tanto en su crecimiento como en su uso, principalmente. Se ejemplifica todo ello en el grupo de los poliquetos, del que el Museo Nacional de Ciencias Naturales de Madrid (MNCN) cuenta con una estimable colección, y se comparan los resultados, según varios parámetros seleccionados, con los de otras colecciones de poliquetos de diversas instituciones de todo el mundo.[EN] Natural History collections are a basic and essential tool for scientific research, the study of the distribution in the past of many species of animals and plants and the History of Science. As well as the scientific aspect of these collections, stand outs other uses as the historic one, the educational and the aesthetic. All these are reasons that show the importance of an effective management of the Natural History collections as well as the several tasks related to it, as consults, visits, scientific loans and educational activities. In this article various criteria and useful parameters are provided for evaluating the curatorial state of a Natural History collection and its evolution, both in growth and use mainly. Finally, an example based on the Polychaeta, an estimable group in the Invertebrates Collection of the Museo Nacional de Ciencias Naturales of Madrid (MNCN), is provided. The results of several selected parameters are compared with other Polychaeta collections from several institutions around the world.Peer reviewe