ResearchPad - embryonic-stem-cells-induced-pluripotent-stem-cells https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[Sphingosine kinases protect murine embryonic stem cells from sphingosine‐induced cell cycle arrest]]> https://www.researchpad.co/article/elastic_article_7044 To test the function of the S1P signaling pathway in ESCs, conditional sphingosine kinase null mouse embryonic stem cell (mESC) lines were created. Sphk1 fl/fl ; Sphk2 −/− mice were crossed, and embryonic blastocysts used to derive mESC lines. Expression of Cre recombinase allows for excision of Sphk1 and produces sphingosine kinase null cells, which become blocked at G2/M due to excessive sphingosine.

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<![CDATA[Deciphering retinal diseases through the generation of three dimensional stem cell-derived organoids: Concise Review]]> https://www.researchpad.co/article/Ne9be9336-ce2d-4dc4-b4d2-a7b5ffb863a5

Abstract

Three‐dimensional (3D) retinal organoids, in vitro tissue structures derived from self‐organizing cultures of differentiating human embryonic stem cells or induced pluripotent stem cells, could recapitulate some aspects of the cytoarchitectural structure and function of the retina in vivo. 3D retinal organoids display huge potential for the investigation of the pathogenesis of monogenic hereditary eye diseases that are related to the malfunction or degeneration of photoreceptors or retinal ganglion cells by providing an effective in vitro tool with multiple applications. In combination with recent genome editing tools, 3D retinal organoids could also represent a reliable and renewable source of transplantable cells for personalized therapies. In this review, we describe the recent advances in human pluripotent stem cells‐derived retinal organoids, determination of their histoarchitecture, complexity, and maturity. We also discuss their application as a means to decipher the pathogenesis of retinal diseases, as well as the main drawbacks and challenges. stem cells 2019;37:1496–1504

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<![CDATA[Insulin Stimulates PI3K/AKT and Cell Adhesion to Promote the Survival of Individualized Human Embryonic Stem Cells]]> https://www.researchpad.co/article/N3657288c-0317-4356-bc58-5b896d871318

Abstract

Insulin is present in most maintenance media for human embryonic stem cells (hESCs), but little is known about its essential role in the cell survival of individualized cells during passage. In this article, we show that insulin suppresses caspase cleavage and apoptosis after dissociation. Insulin activates insulin‐like growth factor (IGF) receptor and PI3K/AKT cascade to promote cell survival and its function is independent of rho‐associated protein kinase regulation. During niche reformation after passaging, insulin activates integrin that is essential for cell survival. IGF receptor colocalizes with focal adhesion complex and stimulates protein phosphorylation involved in focal adhesion formation. Insulin promotes cell spreading on matrigel‐coated surfaces and suppresses myosin light chain phosphorylation. Further study showed that insulin is also required for the cell survival on E‐cadherin coated surface and in suspension, indicating its essential role in cell–cell adhesion. This work highlights insulin's complex roles in signal transduction and niche re‐establishment in hESCs. stem cells 2019;37:1030–1041

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<![CDATA[BIN1 Induces the Formation of T‐Tubules and Adult‐Like Ca2+ Release Units in Developing Cardiomyocytes]]> https://www.researchpad.co/article/5c52ba14d5eed0c4848adffe

Abstract

Human embryonic stem cell‐derived cardiomyocytes (hESC‐CMs) are at the center of new cell‐based therapies for cardiac disease, but may also serve as a useful in vitro model for cardiac cell development. An intriguing feature of hESC‐CMs is that although they express contractile proteins and have sarcomeres, they do not develop transverse‐tubules (T‐tubules) with adult‐like Ca2+ release units (CRUs). We tested the hypothesis that expression of the protein BIN1 in hESC‐CMs promotes T‐tubules formation, facilitates CaV1.2 channel clustering along the tubules, and results in the development of stable CRUs. Using electrophysiology, [Ca2+]i imaging, and super resolution microscopy, we found that BIN1 expression induced T‐tubule development in hESC‐CMs, while increasing differentiation toward a more ventricular‐like phenotype. Voltage‐gated CaV1.2 channels clustered along the surface sarcolemma and T‐tubules of hESC‐CM. The length and width of the T‐tubules as well as the expression and size of CaV1.2 clusters grew, as BIN1 expression increased and cells matured. BIN1 expression increased CaV1.2 channel activity and the probability of coupled gating within channel clusters. Interestingly, BIN1 clusters also served as sites for sarcoplasmic reticulum (SR) anchoring and stabilization. Accordingly, BIN1‐expressing cells had more CaV1.2‐ryanodine receptor junctions than control cells. This was associated with larger [Ca2+]i transients during excitation–contraction coupling. Our data support the view that BIN1 is a key regulator of T‐tubule formation and CaV1.2 channel delivery. By studying the role of BIN1 during the differentiation of hESC‐CMs, we show that BIN1 is also important for CaV1.2 channel clustering, junctional SR organization, and the establishment of excitation–contraction coupling. stem cells 2019;37:54–64

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