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Background Wnt/β-catenin signaling is important in development and differentiation of melanocytes. Objective The object of this study was to evaluate the effects of several Wnt/β-catenin signaling inhibitors on pigmentation using melanoma cells. Methods Melanoma cells were treated with Wnt/β-catenin signaling inhibitors, and then melanin content and tyrosinase activity were checked. Results Although some inhibitors showed slight inhibition of pigmentation, we failed to observe potential inhibitory effect of those chemicals on pigmentation of HM3KO melanoma cells. Rather, one of powerful Wnt/β-catenin signaling inhibitors, ICG-001, increased the pigmentation of HM3KO melanoma cells. Pigmentation-enhancing effect of ICG-001 was reproducible in other melanoma cell line MNT-1. Consistent with these results. ICG-001 increased the expression of pigmentation-related genes, such as MITF, tyrosinase and TRP1. When ICG-001 was treated, the phosphorylation of CREB was significantly increased. In addition, ICG-001 treatment led to quick increase of intracellular cAMP level, suggesting that ICG-001 activated PKA signaling. The blockage of PKA signaling with pharmaceutical inhibitor H89 inhibited the ICG-001-induced pigmentation significantly. Conclusions These results suggest that PKA signaling is pivotal in pigmentation process itself, while the importance of Wnt/β-catenin signaling should be emphasized in the context of development and differentiation. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine the influence of cocultured adipose-derived stromal cells (ASCs) in enhancing the osteogenic differentiation and angiogenesis of bone marrow stromal cells (BMSCs) as well as the underlying mechanism and the optimal ratio. Two in vitro coculture models, segregated cocultures using transwell and mixed cocultures, were employed to assess the indirect and direct effects of coculture respectively. Coculture was carried out for 14 days using 1 × 105 BMSCs and ASCs of variable number. BMSCs, ASCs, or both were seeded in PLGA scaffold and implanted in the subcutaneous tissue of 25 nude mice for in vivo analysis of angiogenesis. To evaluate the orthotopic bone formation, critical size calvarial defects were created on 20 mice, and implanted with hydroxyapatite/β-tricalcium phosphate granules plus BMSCs, ASCs, or both. From both transwell and mixed coculture model, 1 × 105 BMSCs cocultured with 0.5 × 105 ASCs showed significantly greater osteogenic differentiation and mineralization than BMSCs alone. The mixed ASC/BMSC coculture at or above a ratio of 0.5/1 showed increased secretion of vascular endothelial growth factor (VEGF), and induced effective tube formation from human umbilical vein endothelial cells, which were comparable to ASCs. Cytokine profiling assay and gene expression study showed elevated levels of angiogenic factors VEGF and CXCL1, osteogenic factor Wnt5a as well as transforming growth factor (TGF)-βR1 and SMAD3 from BMSCs when cocultured with ASCs. After 5 weeks of implantation, polylactic-co-glycolic acid (PLGA)-ASCs-BMSCs had a number of vascular structures comparable to PLGA-ASCs and significantly greater than PLGA-BMSCs. Calvarial defects treated with ceramic/BMSCs/ASCs had greater area of repair and better reconstitution of osseous structure than the defects treated with ceramic/ASCs or ceramic/BMSCs after 10 weeks. In conclusion, ASCs added to BMSCs promoted osteogenesis and angiogenesis at the optimal ASC/BMSC ratio of 0.5/1. [ABSTRACT FROM AUTHOR]

Abstract: The purpose of this study was to investigate the chondrogenic features of human induced pluripotent stem cells (hiPSCs) and examine the differences in the chondrogenesis between hiPSCs and human bone marrow-derived MSCs (hBMMSCs). Embryoid bodies (EBs) were formed from undifferentiated hiPSCs. After EBs were dissociated into single cells, chondrogenic culture was performed in pellets and alginate hydrogel. Chondro-induced hiPSCs were implanted in osteochondral defects created on the patellar groove of immunosuppressed rats and evaluated after 12 weeks. The ESC markers NANOG, SSEA4 and OCT3/4 disappeared while the mesodermal marker BMP-4 appeared in chondro-induced hiPSCs. After 21 days of culture, greater glycosaminoglycan contents and better chondrocytic features including lacuna and abundant matrix formation were observed from chondro-induced hiPSCs compared to chondro-induced hBMMSCs. The expression of chondrogenic markers including SOX-9, type II collagen, and aggrecan in chondro-induced hiPSCs was comparable to or greater than chondro-induced hBMMSCs. A remarkably low level of hypertrophic and osteogenic markers including type X collagen, type I collagen and Runx-2 was noted in chondro-induced hiPSCs compared to chondro-induced hBMMSCs. hiPSCs had significantly greater methylation of several CpG sites in COL10A1 promoter than hBMMSCs in either undifferentiated or chondro-induced state, suggesting an epigenetic cause of the difference in hypertrophy. The defects implanted with chondro-induced hiPSCs showed a significantly better quality of cartilage repair than the control defects, and the majority of cells in the regenerated cartilage consisted of implanted hiPSCs. [Copyright &y& Elsevier]

• A practical dual-scale finite element modeling is developed to simulate the hole expansion formability of a hyper-burring steel sheet. • The microscale RVE model could take the pile up of dislocation density near the grain boundaries into account to estimate local strengthening at the grain boundary and inhomogeneous plastic deformation in the grain interior. • The hole expansion simulations with different fracture models showed that HER could be better captured when the fracture criterion considered the stress triaxiality developed in the microstructure. • From the microscopic simulation of hole expansion test, the higher hole expansion ratio could be predicted as the grain size increases and the degree of pile-up decreases. A practical dual-scale finite element model is developed to enable the formability prediction in the hole expansion of a hyper-burring steel sheet. This numerical approach resorts to the isotropic macroscale hole expansion simulation for calculating the deformation histories near the hole edge, since they are known to be the potential fracture initiation site. The deformation histories are used as boundary conditions in the lower microscale model for calculating the local fracture of the steel sheet. The microscale simulation utilizes the dislocation density based constitutive model and a microstructure-based representative volume element (RVE), with realistic grain morphology taken from experimental microscopy. The fracture initiation at the hole edge region is evaluated from the microscale simulation using four frequently employed uncoupled ductile fracture models, which enable the definition of the critical fracture strain. The proposed dual-scale model can better predict the failure initiation and location near the hole edge when the modeling parameters are calibrated taking into account not only the deformation histories of the hole edge, but also the local stress triaxiality. Moreover, the proposed dual-scale model is applied to analyze the microstructure effect on the hole expansion ratio by providing the insights into the effect of grain size and grain boundary characteristics. [ABSTRACT FROM AUTHOR]

Mechanically induced martensitic transformation (MIMT) and consequent plastic flow behavior with respect to austenitic texture were investigated in a lean duplex stainless steel. Different grain sizes and textures with fixed phase fractions were obtained via varying the thermomechanical processes. Nearly random distribution of austenitic orientation exhibited a distinguished flow curve from the others with a major D {4 4 11}〈11 11 8〉 component due to more gradual enhancement of hardening by less martensitic transformation. In order to compare the susceptibility to the transformation with respect to individual austenitic orientations and the experimental textures, interaction energy between the imposed stress and transformation strain was calculated by a classical transformation and a crystal plasticity model. The results indicated that a larger stress imposed on the D component led to higher interaction energy and a steeper progress of MIMT observed in the textured materials. [ABSTRACT FROM AUTHOR]

Furans, thiazoles, fluorene or thiophene incorporated calix[4]pyrrole analogues were synthesized and characterized. The synthesis was achieved by utilization of various building blocks such as 7, 13, 14, 18 and 21. Acid catalyzed condensation of those building blocks with acetone or meso-disubstituted dipyrromethanes afforded desired macrocycles. [Copyright &y& Elsevier]