The simple yet powerful technique of induced pluripotency may eventually supply a wide range of differentiated cells for cell therapy and drug development. However, making the appropriate cells via induced pluripotent stem cells (iPSCs) requires reprogramming of somatic cells and subsequent redifferentiation. Given how arduous and lengthy this process can be, we sought to determine whether it might be possible to convert somatic cells into lineagespecific stem/progenitor cells of another germ layer in one step, bypassing the intermediate pluripotent stage. Here we show that transient induction of the four reprogramming factors (Oct4, Sox2, Klf4, and c-Myc) can efficiently transdifferentiate fibroblasts into functional neural stem/progenitor cells (NPCs) with appropriate signaling inputs. Compared with induced neurons (or iN cells, which are directly converted from fibroblasts), transdifferentiated NPCs have the distinct advantage of being expandable in vitro and retaining the ability to give rise to multiple neuronal subtypes and glial cells. Our results provide a unique paradigm for iPSC-factorbased reprogramming by demonstrating that it can be readily modified to serve as a general platform for transdifferentiation.A lthough successful transdifferentiation from one cell type to another by overexpressing lineage-specific genes in vivo (1, 2) and in vitro (3, 4) has been reported, until recently these methods were only effective for fate switching within the major lineages, i.e., ectoderm, mesoderm, and endoderm. However, the generation of iN cells (5) using neural-specific transcription factors has established that interlineage transdifferentiation is also possible in vitro. These transdifferentiation schemes entail overexpression of different sets of lineage-specific transcription factors. A more recent example reported single-factor transdifferentiation of fibroblasts into blood precursors using long-term ectopic expression of OCT4 (6); through extensive binding to the regulatory regions of key hematopoietic genes, OCT4 also appears to be participating in regulating hematopoietic programs acting as a lineage-specific transcription factor in this context. An important aspect of this study is the ability to generate a mitotically active progenitor population that can be further differentiated into a variety of blood cells-a critical feat that has yet to be accomplished in transdifferentiation to neural and endoderm lineages.In an effort to devise a more general transdifferentiation strategy that might give rise to a broad array of unrelated cell typesincluding lineage-specific precursors-we attempted to direct conventional four iPSC-factor-based reprogramming (7, 8) toward alternative outcomes. Specifically, studies indicating that iPSCs are generated in a sequential and stochastic manner (9-11) led us to hypothesize that we might be able to manipulate cells at an early and epigenetically highly unstable state induced by the reprogramming factors. Different conditions could potentially give rise to a multitude ...

Although the serum-abundant metal-binding protein transferrin (encoded by the Trf gene) is synthesized primarily in the liver, its function in the liver is largely unknown. Here, we generated hepatocyte-specific Trf knockout mice (Trf-LKO), which are viable and fertile but have impaired erythropoiesis and altered iron metabolism. Moreover, feeding Trf-LKO mice a high-iron diet increased their susceptibility to develop ferroptosis-induced liver fibrosis. Importantly, we found that treating Trf-LKO mice with the ferroptosis inhibitor ferrostatin-1 potently rescued liver fibrosis induced by either high dietary iron or carbon tetrachloride (CCl4) injections. In addition, deleting hepatic Slc39a14 expression in Trf-LKO mice significantly reduced hepatic iron accumulation, thereby reducing ferroptosis-mediated liver fibrosis induced by either high dietary iron diet or CCl4 injections. Finally, we found that patients with liver cirrhosis have significantly lower levels of serum transferrin and hepatic transferrin, as well as higher levels of hepatic iron and lipid peroxidation compared to healthy controls. Taken together, these data indicate that hepatic transferrin plays a protective role in maintaining liver function, providing a possible therapeutic target for preventing ferroptosis-induced liver fibrosis.

Photochromic materials have been extensively studied because they are quite attractive and promising for many applications.

No abstract

Well-defined single-crystalline PbS nano- and microstructures including dendrites, multipods, truncated nanocubes, and nanocubes were synthesized in high yield by a simple solution route. Novel star-shaped PbS dendrites with six symmetric arms along the 100 direction, each of which shows one trunk (long axis) and four branches (short axes), have been achieved using Pb(AC)2 and thioacetamide (TAA) as precursors, under the molar ratio Pb(AC)2/TAA = 2/1, at initial reaction temperature 80 degrees C, refluxing for 30 min at 100 degrees C, in the presence of cetyltrimethylammonium bromine (CTAB). The "nanorods" in each branch are parallel to each other in the same plane and are perpendicular to the trunk. The truncated nanocubes mainly bounded by the {100} plane were prepared under a different Pb(AC)2/TAA molar ratio, at initial reaction temperature 40 degrees C, refluxing for 12 h at 100 degrees C. Based on the systematic studies on their shape evolution, a possible growth mechanism of these PbS nano- and microstructures was proposed. The shapes of PbS nanocrystals with face-centered cubic (fcc) structure are mainly determined by the ratio (R) between the growth rates along the (100) and (111) directions. The Pb(AC)2/TAA molar ratio and the initial reaction temperature influence the growth ratio R in the formation of PbS nuclei at an early stage, which results in the final morphology of PbS nanocrystals. Under the current experimental conditions, we can control the PbS shape evolution by simply tuning the molar ratio, the initial reaction temperature, and the period of reaction. Based on the systematic studies on the shape evolution, this approach is expected to be employed for the control-shaped synthesis of other fcc structural semiconductor nanomaterials. The photoluminescence properties were investigated and the prepared nano- and microstructures displayed a very strong luminescence around 600-650 nm at room temperature.

De novo assembled and characterized the radish tuberous root transcriptome; explored the mechanism of radish tuberous root formation; development of EST-SSR markers in radish.

We described the derivation of four stable pluripotent rabbit embryonic stem cell (ESC) lines, one (RF) from blastocysts fertilized in vivo and cultured in vitro and three (RP01, RP02, and RP03) from parthenogenetic blastocysts. These ESC lines have been cultivated for extended periods (RF >1 year, RP01 >8 months, RP02 >8 months, and RP03 >6 months) in vitro while maintaining expression of pluripotent ESC markers and a normal XY or XX karyotype. The ESCs from all lines expressed alkaline phosphatase, transcription factor Oct-4, stage-specific embryonic antigens (SSEA-1, SSEA-3, and SSEA-4), and the tumor-related antigens (TRA-1-60 and TRA-1-81). Similar to human and mouse ESCs, rabbit ESCs expressed pluripotency (Oct-4, Nanog, SOX2, and UTF-1) and signaling pathway genes (fibroblast growth factor, WNT, and transforming growth factor pathway). Morphologically, rabbit ESCs resembled primate ESCs, whereas their proliferation characteristics were more like those seen in mouse ESCs. Rabbit ESCs were induced to differentiate into many cell types in vitro and formed teratomas with derivatives of the three major germ layers in vivo when injected into severe combined immunodeficient mice. Our results showed that pluripotent, stable ESC lines could be derived from fertilized and parthenote-derived rabbit embryos. STEM CELLS 2007;25:481-489

SummaryThe FRUITFULL genes regulate tomato fruit ripening in a redundant manner. They are functional diversely in fruit shape regulation through affecting cellular differentiation and expansion.