204 research outputs found
Human Embryonic Stem Cell Science in Iran: Pioneering in the Muslim World
La recherche sur les cellules souches embryonnaires humaines (CSEh) est un domaine qui a suscité un vif intérêt dans les milieux scientifiques mais aussi financiers. C’est aussi un champ d’investigation source de dilemmes éthiques et de développements politiques encadrant le statut moral de l’embryon humain, les sources d’embryons ou de gamètes humains destinés à la recherche, le clonage ainsi que l’utilisation thérapeutique des cellules souches. Dans le monde Musulman, l’Iran, une nation pionnière de la recherche sur les SCEh, a reporté l’établissement d’une nouvelle lignée de cellules souches dès 2003. Ce pays a aussi établi des recommandations éthiques nationales pour la recherche et la thérapie utilisant les cellules souches. Le présent manuscrit décrit le développement de la science entourant les CSEh ainsi que d’autres accomplissements scientifiques et bioéthiques connexes en Iran. Il explique aussi comment la recherche sur les CSEh est à la fois guidée et réglementée par les lois et principes éthiques issus de l’Islam, et montre comment l’expérience d’un pays en développement peut servir d’exemple à d’autres sociétés similaires. Cet article présente ensuite une brève revue de l’état actuel de la recherche et de la réglementation de ce domaine dans certains pays Musulmans du Moyen-Orient. En conclusion, on peut argumenter autour du fait que, bien que la science et la religion soient des facteurs clés dans les débats actuels autours des CSEh, d’autres facteurs influencent la manière avec laquelle un nouveau savoir est abordé dans des pays ayant par ailleurs la même obédience religieuse ou des intérêts scientifiques similaires.Human embryonic stem cell (hESC) research is a field that has attracted considerable scientific and financial investment and attention in many countries. It is also a field surrounded by ethical controversies and policy developments concerning the moral status of the human embryo, sourcing of human embryos and gametes for research, cloning as well as stem cell (SC) therapy. In the Muslim world, Iran, as a pioneer country in hESC research, reported the establishment of a new SC line in 2003. The country has also established the national ethical guidelines for SC research and therapy. This paper therefore depicts the development of hESC science, as well as some other relevant scientific achievements and bioethics in Iran. It also describes how hESC research is both formed and regulated by Islamic law and ethics, as the experience of a developing country can provide insight to many similar societies. This article then presents a brief review of the current state of this field of science and its regulatory policy in some selected Muslim Middle East countries. In conclusion, it shall argue that, although science and religion are key factors in the current debates around hESC research, additional factors influence the manner in which new knowledge is taken up in countries with the same religious background or scientific interests
Polycaprolactone-templated reduced-graphene oxide liquid crystal nanofibers towards biomedical applications
Here, we report a facile method to generate electrically conductive nanofibers by coating and subsequently chemically reducing graphene oxide (GO) liquid crystals on a polycaprolactone (PCL) mat.</p
Intranuclear localization of EGFP-mouse PPARγ1 in bovine fibroblast cells
Objective: The aim of this study was to clone PPARγ1 cDNA in an appropriate mammalian
expression vector, with a chimeric cDNA form, encompassing PPARγ with enhanced green
fluorescent protein (EGFP) cDNA. This recombinant plasmid will be used for further analyses
to investigate the molecular mechanism of PPARγ1 for neural differentiation process.
Moreover, the nuclear localization of the PPARγ1 protein linked to EGFP marker was chased
by using transient transfection of a constructed plasmid into bovine fibroblast cells.
Materials and Methods: Total RNA was extracted from the fatty tissue of an adult mouse.
Using specific pair primers, PPARγ1 cDNA was synthesized and amplified to produce
the entire length of ORF. RT-PCR products containing PPARγ1 cDNA were treated by
enzymatic digestion and inserted into the pEGFP-C1 downstream from EGFP cDNA. The
constructed vector was used for transformation into bacterial competent cells. Positive
colonies which showed inserted PPARγ1 cDNA were selected for plasmid preparations
and additional analysis was performed to ensure that PPARγ1 cDNA was inserted properly.
Finally, to confirm the intracellular localization of EGFP-PPARγ1, bovine fibroblast
cells were transfected with the recombinant plasmid.
Results: Our results from enzymatic digestion and sequencing confirmed, as expected, that
PPARγ1 cDNA was amplified and cloned correctly. This cDNA gene encompassed 1428 bp.
The related product was entered into the nucleus of bovine fibroblasts after transfection of
its cDNA.
Conclusion: PPARγ1 cDNA was cloned and sorted into nuclear compartments of bovine
fibroblast cells upon transfection
Brief Azacytidine Step Allows The Conversion of Suspension Human Fibroblasts into Neural Progenitor-Like Cells
In recent years transdifferentiation technology has enabled direct conversion of human
fibroblasts to become a valuable, abundant and accessible cell source for patient-specific
induced cell generation in biomedical research. The majority of transdifferentiation approaches
rely upon viral gene delivery which due to random integration with the host
genome can cause genome instability and tumorigenesis upon transplantation. Here, we
provide a simple way to induce neural progenitor-like cells from human fibroblasts without
genetic manipulation by changing physicochemical culture properties from monolayer
culture into a suspension in the presence of a chemical DNA methyltransferase inhibitor
agent, Azacytidine. We have demonstrated the expression of neural progenitor-like markers,
morphology and the ability to spontaneously differentiate into neural-like cells. This
approach is simple, inexpensive, lacks genetic manipulation and could be a foundation for
future chemical neural transdifferentiation and a safe induction of neural progenitor cells
from human fibroblasts for clinical applications
Comprehensive Gene Expression Analysis of Human Embryonic Stem Cells during Differentiation into Neural Cells
Global gene expression analysis of human embryonic stem cells (hESCs) that differentiate into neural cells would help to further define the molecular mechanisms involved in neurogenesis in humans. We performed a comprehensive transcripteome analysis of hESC differentiation at three different stages: early neural differentiation, neural ectoderm, and differentiated neurons. We identified and validated time-dependent gene expression patterns and showed that the gene expression patterns reflect early ESC differentiation. Sets of genes are induced in primary ectodermal lineages and then in differentiated neurons, constituting consecutive waves of known and novel genes. Pathway analysis revealed dynamic expression patterns of members of several signaling pathways, including NOTCH, mTOR and Toll like receptors (TLR), during neural differentiation. An interaction network analysis revealed that the TGFβ family of genes, including LEFTY1, ID1 and ID2, are possible key players in the proliferation and maintenance of neural ectoderm. Collectively, these results enhance our understanding of the molecular dynamics underlying neural commitment and differentiation
Temporal Gene Expression and DNA Methylation during Embryonic Stem Cell Derivation
Objective
Dual inhibition of mitogen-activated protein kinase (MAPK) kinase (also known as MEK) and transforming growth factor β (TGFβ) type I receptors by PD0325901 and SB431542, known as R2i has been introduced as a highly efficient approach to the generation of mouse embryonic stem cells (ESC). In the present study, we investigated the molecular mechanisms underlying ESC derivation in the R2i condition.
Materials and Methods
In this experimental study, zona-free whole E3.5 blastocysts were seeded on mouse embryonic fibroblast (MEF) feeder cells in both R2i and serum conventional media. The isolated inner cell mass (ICM), ESCs and the ICM-outgrowths were collected on days 3, 5 and 7 post-blastocyst culture for quantitative real time- polymerase chain reaction (qRT-PCR) analysis as well as to assess the DNA methylation status at the time points during the transition from ICM to ESC.
Results
qRT-PCR revealed a significantly higher expression of the pluripotency-related genes (Oct4, Nanog, Sox2, Rex1, Dppa3, Tcf3, Utf1, Nodal, Dax1, Sall4 and β-Catenin) and lower expression of early differentiation genes (Gata6, Lefty2 and Cdx2) in R2i condition compared to the serum condition. Moreover, the upstream region of Oct4 and Nanog showed a progressive increase in methylation levels in the upstream regions of the genes following in R2i or serum conditions, followed by a decrease of DNA methylation in ESCs obtained under R2i. However, the methylation level of ICM outgrowths in the serum condition was much higher than R2i, at levels that could have a repressive effect and therefore explain the absence of expression of these two genes in the serum condition.
Conclusion
Our investigation revealed that generation of ESCs in the ground-state of pluripotency could be achieved by inhibiting the MEK and TGF-β signaling pathways in the first 5 days of ESC derivation
Stem Cells from Human Exfoliated Deciduous Tooth Exhibit Stromal-Derived Inducing Activity and Lead to Generation of Neural Crest Cells from Human Embryonic Stem Cells
Objective: The neural crest is a transient structure of early vertebrate embryos that generates
neural crest cells (NCCs). These cells can migrate throughout the body and produce
a diverse array of mature tissue types. Due to the ethical and technical problems surrounding
the isolation of these early human embryo cells, researchers have focused on in
vitro studies to produce NCCs and increase their knowledge of neural crest development.
Materials and Methods: In this experimental study, we cultured human embryonic stem
cells (hESCs) on stromal stem cells from human exfoliated deciduous teeth (SHED) for a
two-week period. We used different approaches to characterize these differentiated cells
as neural precursor cells (NPCs) and NCCs.
Results: In the first co-culture week, hESCs appeared as crater-like structures with marginal
rosettes. NPCs derived from these structures expressed the early neural crest marker
p75 in addition to numerous other genes associated with neural crest induction such as
SNAIL, SLUG, PTX3 and SOX9. Flow cytometry analysis showed 70% of the cells were
AP2/P75 positive. Moreover, the cells were able to self-renew, sustain multipotent differentiation
potential, and readily form neurospheres in suspension culture.
Conclusion: SHED, as an adult stem cell with a neural crest origin, has stromal-derived
inducing activity (SDIA) and can be used as an NCC inducer from hESCs. These cells
provide an invaluable resource to study neural crest differentiation in both normal and
disordered human neural crest development
Long-Term Follow-up of Autologous Fibroblast Transplantation for Facial Contour Deformities, A Non-Randomized Phase IIa Clinical Trial
Objective: Recently, the promising potential of fibroblast transplantation has become a novel modality for skin
rejuvenation. We investigated the long-term safety and efficacy of autologous fibroblast transplantation for participants
with mild to severe facial contour deformities.
Materials and Methods: In this open-label, single-arm phase IIa clinical trial, a total of 57 participants with wrinkles
(n=37, 132 treatment sites) or acne scars (n=20, 36 treatment sites) who had an evaluator’s assessment score of
at least 2 out 7 (based on a standard photo-guide scoring) received 3 injections of autologous cultured fibroblasts
administered at 4-6 week intervals. Efficacy evaluations were performed at 2, 6, 12, and 24 months after the final
injection based on evaluator and patient’s assessment scores.
Results: Our study showed a mean improvement of 2 scores in the wrinkle and acne scar treatment sites. At sixth
months after transplantation, 90.1% of the wrinkle sites and 86.1% of the acne scar sites showed at least a one grade
improvement on evaluator assessments. We also observed at least a 2-grade improvement in 56.1% of the wrinkle
sites and 63.9% of the acne scar sites. A total of 70.5% of wrinkle sites and 72.2% of acne scar sites were scored as
good or excellent on patient assessments. The efficacy outcomes remained stable up to 24-month. We did not observe
any serious adverse events during the study.
Conclusion: These results have shown that autologous fibroblast transplantation could be a promising remodeling
modality with long-term corrective ability and minimal adverse events (Registration Number: NCT01115634)
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