Key Points Notch1 induction promotes specification of hemogenic endothelial cells during embryonic stem cell differentiation. Foxc2 functions downstream of Notch in specification of hemogenic endothelium in mouse and zebrafish embryos.

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BackgroundEndothelial cells have been shown to mediate angiogenesis in ischemic injury sites and contribute to the repair of damaged tissues. However, the treatment of ischemic disease requires a significant number of endothelial cells, which are difficult to isolate from patients. Embryonic stem cells have been considered a potential source of therapeutic cells due to their unlimited self-renewal and pluripotent properties. With regard to vascular development, Notch1 has been established as a key regulator of the specification of arterial endothelial cells.MethodsUsing a doxycycline-induced expression system of the intracellular domain of Notch1, we explored the role of Notch1 in the differentiation of embryonic stem cells to arterial endothelial cells. The therapeutic effect of the arterial endothelial cells was investigated in a murine hindlimb ischemia model. The blood perfusion rate in the ischemic limb was determined by laser Doppler perfusion imaging, and vasculogenesis was quantified using immunocytochemistry.ResultsInduced expression of the intracellular domain of Notch1 increased the levels of endothelial markers, such as CD31 and VE-cadherin, in differentiated endothelial cells. Induction of intracellular domain of Notch1 stimulated expression of the arterial-type endothelial cell markers (Nrp1 and Ephrin B2), but not the venous-type endothelial cell markers (Nrp2 and Coup-TFII). In addition, overexpression of intracellular domain of Notch1 resulted in increased expression of CXCR4, a chemokine receptor involved in vascular development. Induction of intracellular domain of Notch1 increased endothelial tube formation and migration of differentiated endothelial cells. Intramuscular administration of Notch1-induced arterial endothelial cells was more effective than administration of the control endothelial cells in restoring the blood flow in an ischemic hindlimb mouse model. Transplantation of Notch1-induced arterial endothelial cells augmented the number of blood vessels and incorporation of endothelial cells into newly formed blood vessels.ConclusionsThese results suggest that Notch1 promotes endothelial maturation and arterial specification during the differentiation of embryonic stem cells to endothelial cells and increases the angiogenic potential of endothelial cells.Electronic supplementary materialThe online version of this article (10.1186/s13287-018-0945-7) contains supplementary material, which is available to authorized users.

BackgroundTransforming growth factor-β1 (TGF-β1) induces the differentiation of human adipose tissue-derived mesenchymal stem cells (hASCs) into smooth muscle cells. Lipid rafts are cholesterol-rich microdomains in cell membranes that reportedly play a key role in receptor-mediated signal transduction and cellular responses. In order to clarify whether lipid rafts are involved in TGF-β1-induced differentiation of hASCs into smooth muscle cells, we analyzed the lipid raft proteome of hASCs.Methods and ResultsPretreatment of hASCs with the lipid raft disruptor methyl-β-cyclodextrin abrogated TGF-β1-induced expression of α-smooth muscle actin, a smooth muscle cell marker, suggesting a pivotal role of lipid rafts in TGF-β1-induced differentiation of hASCs to smooth muscle cells. Sucrose density gradient centrifugation along with a shotgun proteomic strategy using liquid chromatography-tandem mass spectrometry identified 1002 individual proteins as the lipid raft proteome, and 242 of these were induced by TGF-β1 treatment. ADAM12, a disintegrin and metalloproteases family member, was identified as the most highly up-regulated protein in response to TGF-β1 treatment. TGF-β1 treatment of hASCs stimulated the production of both ADAM12 protein and mRNA. Silencing of endogenous ADAM12 expression using lentiviral small hairpin RNA or small interfering RNA abrogated the TGF-β1-induced differentiation of hASCs into smooth muscle cells.ConclusionsThese results suggest a pivotal role for lipid raft-associated ADAM12 in the TGF-β1-induced differentiation of hASCs into smooth muscle cells.

Embryonic stem (ES) cells are pluripotent cells characterized by self-renewability and differentiation potential. Induced pluripotent stem (iPS) cells are ES cell-equivalent cells derived from somatic cells by the introduction of core reprogramming factors. ES and iPS cells are important sources for understanding basic biology and for generating therapeutic cells for clinical applications. Tribbles homolog 2 (Trib2) functions as a scaffold in signaling pathways. However, the relevance of Trib2 to the pluripotency of ES and iPS cells is unknown. In the present study, we elucidated the importance of Trib2 in maintaining pluripotency in mouse ES cells and in generating iPS cells from somatic cells through the reprogramming process. Trib2 expression decreased as ES cells differentiated, and Trib2 knockdown in ES cells changed their colony morphology while reducing the activity of alkaline phosphatase and the expression of the pluripotency marker genes Oct4, Sox2, Nanog and Klf4. Trib2 directly interacted with Oct4 and elevated Oct4 promoter activity. During the generation of iPS cells, Trib2 knockdown decreased the reprogramming efficiency of mouse embryonic fibroblasts, whereas Trib2 overexpression significantly increased their reprogramming efficiency. In summary, our results suggest that Trib2 is important for maintaining self-renewal in ES cells and for pluripotency induction during the reprogramming process.

Purpose: This study was aimed at identifying levels of compliance of patients with metabolic syndrome and the factors influencing their compliance. Methods: Data were collected from patients with metabolic syndrome at K medical center in 2009 using questionnaires. The data were analyzed using ANOVA, t-test, Scheffe test, Pearson correlation, and stepwise multiple regression. Results: The mean score of health behavior compliance was 2.82 (range: 1.43~3.87). Of the factors significantly influencing compliance with health behavior, health perception, exercise efficacy, age and perceived severity explained the 42.8% variance of compliance with health behavior. The factor explaining the highest level of variance was health perception. Conclusion: It is essential for health professionals to consider the aforementioned four factors when developing interventions to increase compliance with health behavior of the patient with metabolic syndrome.

Reprogramming of somatic cells to pluripotent cells requires the introduction of factors driving fate switches. Viral delivery has been the most efficient method for generation of induced pluripotent stem cells. Transfection, which precedes virus production, is a commonly-used process for delivery of nucleic acids into cells. The aim of this study is to evaluate the efficiency of PLGA/ bPEI nanoparticles in transfection and virus production. Using a modified method of producing PLGA nanoparticles, PLGA/bPEI-DNA nanoparticles were examined for transfection efficiency and virus production yield in comparison with PLGA-DNA, bPEI-DNA nanoparticles or liposome-DNA complexes. After testing various ratios of PLGA, bPEI, and DNA, the ratio of 6:3:1 (PLGA:bPEI:DNA, w/w/w) was determined to be optimal, with acceptable cellular toxicity. PLGA/bPEI-DNA (6:3:1) nanoparticles showed superior transfection efficiency, especially in multiple gene transfection, and viral yield when compared with liposome-DNA complexes. The culture supernatants of HEK293FT cells transfected with PLGA/bPEI-DNA of viral constructs containing reprogramming factors (Oct4, Sox2, Klf4, or c-Myc) successfully and more efficiently generated induced pluripotent stem cell colonies from mouse embryonic fibroblasts. These results strongly suggest that PLGA/bPEI-DNA nanoparticles can provide significant advantages in studying the effect of multiple factor delivery such as in reprogramming or direct conversion of cell fate.