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Concept: Leukemia inhibitory factor

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Aim: To develop a clinically applicable MRI technique for tracking stem cells in matrix-associated stem-cell implants, using the US FDA-approved iron supplement ferumoxytol. Materials & methods: Ferumoxytol-labeling of adipose-derived stem cells (ADSCs) was optimized in vitro. A total of 11 rats with osteochondral defects of both femurs were implanted with ferumoxytol- or ferumoxides-labeled or unlabeled ADSCs, and underwent MRI up to 4 weeks post matrix-associated stem-cell implant. The signal-to-noise ratio of different matrix-associated stem-cell implant was compared with t-tests and correlated with histopathology. Results: An incubation concentration of 500 µg iron/ml ferumoxytol and 10 µg/ml protamine sulfate led to significant cellular iron uptake, T2 signal effects and unimpaired ADSC viability. In vivo, ferumoxytol- and ferumoxides-labeled ADSCs demonstrated significantly lower signal-to-noise ratio values compared with unlabeled controls (p < 0.01). Histopathology confirmed engraftment of labeled ADSCs, with slow dilution of the iron label over time. Conclusion: Ferumoxytol can be used for in vivo tracking of stem cells with MRI. Original submitted 28 February 2012; Revised submitted 8 November 2012.

Concepts: Iron, Cell division, Stem cell, In vivo, In vitro, Inner cell mass, Signal-to-noise ratio, Leukemia inhibitory factor

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A receptive endometrium is essential for maternal-embryonic molecular communication during implantation. However, the specific molecular regulatory mechanisms of the endometrial capacity remain poorly understood. Here, we examined activating transcription factor 3 (ATF3) expression in human endometria and the functional effect of ATF3 on embryo attachment in vitro.

Concepts: DNA, Pregnancy, Transcription, Embryo, P53, Endometrium, Implantation, Leukemia inhibitory factor

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The cytokine Leukemia inhibitory factor (LIF) is essential for rendering the uterus receptive for blastocyst implantation. In mice LIF receptor expression (LIFR) is largely restricted to the uterine luminal epithelium (LE). LIF, secreted from the endometrial glands (GE) binds to the LIFR, activating the Jak-Stat3 signaling pathway in the LE. JAK-STAT activation converts the LE to a receptive state so that juxtaposed blastocysts begin to implant. To specifically delete the LIFR in the LE we derived a line of mice in which Cre recombinase was inserted into the endogenous Lactoferrin gene (Ltf-Cre). Lactoferrin expression in the LE is induced by E2 and we demonstrate that Cre recombinase activity is restricted to the LE and GE. To determine the requirement of the LIFR in implantation, we derived an additional mouse line carrying a conditional (floxed) Lifrflx/flx gene. Crossing Ltf-Cre mice with Lifrflx/flx mice, generated Lifrflx/Δ:LtfCre/+ females that were overtly normal, but infertile. Many of these females, despite repeated matings, did not become pregnant. Unimplanted blastocysts were recovered from the Lifrflx/Δ:LtfCre/+ uteri and when transferred to WT recipients, implanted normally, indicating that uterine receptivity rather than the embryo’s competency is compromised. The loss of Lifr results in both the failure for STAT3 to translocate to the LE nuclei and a reduction in the expression of the LIF regulated gene Msx1 that regulates uterine receptivity. These results reveal that uterine expression of the LIFR is essential for embryo implantation, and further define the components of the LIF signaling pathway necessary for effective implantation.

Concepts: Pregnancy, Embryo, Uterus, Endometrium, Cervix, Implantation, Blastocyst, Leukemia inhibitory factor

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The embryo implantation is crucial step for successful pregnancy. Diverse factors including adhesion molecules, growth factors, and cytokines are important to the embryo implantation through improving endometrial receptivity. Benzoic acid (BA), a component of various plants, has been shown to have anti-fungal and anti-oxidant effects. However, the effect of BA on the embryo implantation remains unknown. Here, we showed the contribution of BA for the enhancement of endometrial receptivity through the leukemia inhibitory factor (LIF)-dependent increase of integrin αV, β3, and β5 expression. Furthermore, in vivo study using mifepristone-induced implantation failure model showed that BA definitely improves the numbers of implantation embryos. Taken together, we suggest that BA has a novel function for embryo implantation through the up-regulation of LIF-mediated integrins, and may be a candidate for therapeutic medicine to increase the pregnancy rate.

Concepts: Pregnancy, Embryo, Uterus, In vivo, Endometrium, Implantation, Integrin, Leukemia inhibitory factor

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Wnt signaling plays an important role in the self-renewal and differentiation of stem cells. The secretion of Wnt ligands requires Evi (also known as Wls). Genetically ablating Evi provides an experimental approach to studying the consequence of depleting all redundant Wnt proteins, and overexpressing Evi enables a nonspecific means of increasing Wnt signaling. We generated Evi-deficient and Evi-overexpressing mouse embryonic stem cells (ESCs) to analyze the role of autocrine Wnt production in self-renewal and differentiation. Self-renewal was reduced in Evi-deficient ESCs and increased in Evi-overexpressing ESCs in the absence of leukemia inhibitory factor, which supports the self-renewal of ESCs. The differentiation of ESCs into cardiomyocytes was enhanced when Evi was overexpressed and teratoma formation and growth of Evi-deficient ESCs in vivo were impaired, indicating that autocrine Wnt ligands were necessary for ESC differentiation and survival. ESCs lacking autocrine Wnt signaling had mitotic defects and showed genomic instability. Together, our study demonstrates that autocrine Wnt secretion is important for the survival, chromosomal stability, differentiation, and tumorigenic potential of ESCs.

Concepts: DNA, Gene, Genetics, Cell, Stem cell, Chromosome, Embryonic stem cell, Leukemia inhibitory factor

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Adenomyosis was found to have negative impacts on embryo implantation. Leukemia inhibitory factor (LIF), proposed to be a molecular marker for endometrial receptivity, works through the LIF receptor (LIFR) on both the embryo and the endometrium. We aimed to evaluate the endometrial expression of LIF and LIFR and its subsequent signaling in patients with adenomyosis during the window of implantation (WOI).

Concepts: Pregnancy, Embryo, Uterus, Endometrium, Implantation, Endometriosis, Leukemia inhibitory factor, Works

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Brain injuries, such as cerebral hypoxia-ischemia (H-I), induce a regenerative response from the neural stem/progenitors (NSPs) of the subventricular zone (SVZ); however, the mechanisms that regulate this expansion have not yet been fully elucidated. The Notch- Delta-Serrate-Lag2 (DSL) signaling pathway is considered essential for the maintenance of neural stem cells, but it is not known if it is necessary for the expansion of the NSPs subsequent to perinatal H-I injury. Therefore, the aim of this study was to investigate whether this pathway contributes to NSP expansion in the SVZ after H-I and, if so, to establish whether this pathway is directly induced by H-I or regulated by paracrine factors. Here we report that Notch1 receptor induction and one of its ligands, Delta-like 1, precedes NSP expansion after perinatal H-I in P6 rat pups and that this increase occurs specifically in the most medial cell layers of the SVZ where the stem cells reside. Pharmacologically inhibiting Notch signaling in vivo diminished NSP expansion. With an in vitro model of H-I, Notch1 was not induced directly by hypoxia, but was stimulated by soluble factors, specifically leukemia inhibitory factor, produced by astrocytes within the SVZ. These data confirm the importance both of the Notch-DSL signaling pathway in the expansion of NSPs after H-I and in the role of the support cells in their niche. They further support the body of evidence that indicates that leukemia inhibitory factor is a key injury-induced cytokine that is stimulating the regenerative response of the NSPs. © 2016 Wiley Periodicals, Inc.

Concepts: Protein, Neuron, Stem cell, In vivo, Neurogenesis, In vitro fertilisation, In vitro, Leukemia inhibitory factor

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Limbal stem cell deficiency (LSCD) is now established as a distinct entity with a spectrum of clinical manifestations. Bilateral LSCD presents a unique set of challenges to the clinician dealing with ocular surface disease, due to the underlying causes, clinical presentation, and adnexal status, as well as lack of a source of autologous limbal stem cells. Various surgical modalities have been described to achieve visual rehabilitation in patients with bilateral LSCD. These can primarily be divided into cell-based therapies and implantation of keratoprostheses. In this review, the surgical options for management of bilateral LSCD, including autologous and allogeneic cell-based therapies and different types of keratoprostheses are described and classified. The indications, prerequisites, technique, results and complications of each modality are discussed. Based on the status of the ocular surface, an algorithm for choosing appropriate surgical management for vision restoration in bilateral LSCD has been proposed.

Concepts: Medicine, Cell, Cell division, Stem cell, Cell biology, Organ transplant, Inner cell mass, Leukemia inhibitory factor

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After in vivo implantation of cell-loaded devices, only the cells close to the capillaries can obtain nutrients to maintain their functions. It is known that factors secreted by stem cells, rather than stem cells themselves, are fundamental to guarantee new vascularization in the area of implant.

Concepts: Cell, Embryo, Inner cell mass, Fourier series, Leukemia inhibitory factor

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In the present study, we investigated the role of Paeonia lactiflora Pall. extract on embryo implantation in vitro and in vivo. A polysaccharides depleted-water extract of P. lactiflora (PL-PP) increased LIF expression in human endometrial Ishikawa cells at non-cytotoxic doses. PL-PP significantly increased the adhesion of the human trophectoderm-derived JAr spheroids to endometrial Ishikawa cells. PL-PP-induced LIF expression was decreased in the presence of a p38 kinase inhibitor SB203580 and an MEK/ERK inhibitor U0126. Furthermore, endometrial LIF knockdown by shRNA reduced the expression of integrins β3 and β5 and adhesion of JAr spheroids to Ishikawa cells. In vivo administration of PL-PP restored the implantation of mouse blastocysts in a mifepristone-induced implantation failure mice model. Our results demonstrate that PL-PP increases LIF expression via the p38 and MEK/ERK pathways and favors trophoblast adhesion to endometrial cells.

Concepts: Pregnancy, Embryo, In vivo, In vitro, Endometrium, Implantation, Blastocyst, Leukemia inhibitory factor