Summary Mesenchymal stem cells (MSCs

With contrasting observations on the effects of b-catenin on hematopoietic stem cells (HSCs), the precise role of Wnt/b-catenin signals on HSC regulation remains unclear. Here, we show a distinct mode of Wnt/b-catenin signal that can regulate HSCs in a stroma-dependent manner. Stabilization of b-catenin in the bone marrow stromal cells promoted maintenance and self-renewal of HSCs in a contactdependent manner, whereas direct stabilization in hematopoietic cells caused loss of HSCs. Interestingly, canonical Wnt receptors and b-catenin accumulation were predominantly enriched in the stromal rather than the hematopoi-

This work was supported by the KRIBB Creative Research Program (KCS3051312); the STP project (DTM0111221) of the Ministry of Knowledge & Economy and the Basic Science Research Program (RBM0271312) of the National Research Foundation of Korea (NRF) from the Ministry of Education, Science & Technology. There are no conflicts of interest.

IntroductionHematopoietic stem cells (HSCs) constitute a rare subpopulation in hematopoietic tissues and are uniquely defined by their ability to divide many times with full retention of their pluripotentiality. 1 This self-renewal function underlies the ability of HSCs to produce new blood cells throughout the life of the individual. It also allows them to regenerate the entire blood-forming system in vivo, including the HSC compartment, following their transplantation into irradiated recipients. 2,3 In mice, the ability of individual HSCs to permanently reconstitute all blood-cell lineages provides a functional end point for the specific quantification of HSCs in limiting-dilution transplantation assays. 4 The cells thus defined are operationally referred to as competitive repopulating units (CRUs), since these cells must compete with other HSCs whose presence is required for the survival of the host mice.Expansion of the HSC (CRU) population normally occurs in vivo during fetal and early adulthood. 5 Thereafter, the number of these cells remains stable with self-renewal divisions exactly balancing HSC losses by differentiation or death. However, a rapid and extensive net expansion of HSCs can be reinitiated in vivo following damage to the hematopoietic system. 6 Accumulating evidence points to the involvement of both extrinsic cues (eg, Steel factor, factors that activate gp130, 7 notch ligands, 8 and Wnt 9 ) as well as intrinsic regulators (eg, p21 cip1/waf1 , 10 Bmi-1, 11,12 and HoxB4 13-15 ) in controlling HSC self-renewal responses following their mitogenic activation in vitro or in vivo. Relatively little, however, is known about the signaling intermediates that direct or can modulate changes in HSC self-renewal when these cells are stimulated to proliferate in vivo.Signal transducer and activator of transcription 3 (STAT3) is an intermediate signaling molecule that allows ligand-induced signals from gp130 and the granulocyte colony-stimulating factor (G-CSF) receptor, and from various endogenous nonreceptor kinases such as Src, 16,17 to transactivate specific target genes. A key event in this process is the induced phosphorylation of the Tyr 705 residue in the Src-homology 2 (SH2) domain of STAT3, which then leads to the formation of STAT3 dimers and their translocation into the nucleus. Distinct biologic roles of STAT3 in various types of tissues including hematopoietic cells have been described in several studies. 18 In hematopoietic tissue, we showed that the forced expression of a dominant-negative (dn) form of Stat3 in fetal liver cells markedly reduced the competitive repopulating activity of the transduced HSCs in irradiated recipients of cotransplanted normal adult bone marrow cells. However, neither the proliferation nor the differentiation of slightly more mature progenitors in the original suspension of dnSTAT3-transduced fetal liver cells (detected in vivo as colony-forming units-spleen, CFU-Ss, or in vitro as colony-forming cells, CFCs) was affected. 19 Subsequently, it was found that induc...

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There are many factors to influence the amount of terpene at the forest. However, it is poorly understood whether the amount is altered by meteorological factors. In order to study correlation analysis between terpene amount and meteorological(i.e., temperature, humidity, wind speed, solar radiation) and environmental factors(i.e., oxygen, carbonb dioxide) at the artificial coniferous forest of Chamaecyparis obtusa (site 1) and Cryptomeria japonica (site 2) nearby the 1 st reservoir at Mt. Moodeung, the research was executed during April to November in 2011. Forest density at site 1 was 1,692 trees/ha, being occupied with 87.2% of Chamaecyparis obtusa, higher than 925 trees/ha at site 2. Carbon dioxide at site 1 was in the range of 385∼410 ppm in June, similar to at Anmyundo(395 ppm in 2010). Solar radiation has positive correlation with ambient temperature and inversely negative with relative humidity. Main species of terpene released were α -pinene, camphene, β-pinene, cymene, δ-limonene and camphor at two sites and terpene was more effluent at spring and summer than at fall. The large amount of terpene was emitted in the afternoon than in the morning under the influence of the wind speed and the topographical property. The terpene amount has positive correlation with relative humidity and oxygen, and negative with wind speed and soil temperature. Because correlations of α-pinene and other terpene materials showed statistically significant within p=0.01. α-pinene could be suggested as the basic material in explaining the amount of other terpene materials.

The present study was performed to know the effects of taurine on the lipid level of plasma and liver, lipid peroxidation and antioxidative enzyme activities of liver tissue in ovariectomized (OVX) rats fed cholesterol. Twenty-four female SD rats (200 ± 5 g) were grouped; sham and ovariectomy groups, which were each randomly subgrouped; fed control and control supplemented with taurine (20 g/kg diet). The serum total cholesterol, TG (triglyceride), LDL-cholesterol, athrogenic index, and HDL-cholesterol of taurine diet group were not statistically different. Also the levels of liver total cholesterol, triglyceride were not considerably different in different diets. The lipid peroxidation of malondialdehyde concentration was considerably lower in taurine-feeding group than control-feeding group in ovariectomy group. The superoxide dismutase activity in liver tissue was significantly higher in rats fed taurine than in rats fed control diet in OVX rats. GSH-Px (glutathione peroxidase) activity was statistically greater at the rats fed taurine diets compared to rats fed control diet in ovariectomy group. Activity of catalase was higher in taurine group than in control group in ovariectomy group, but it was not significantly different. In conclusion, taurine supplementation was beneficial on antioxidative enzyme activities of liver tissue in ovariectomized rats fed cholesterol.